See the way the Kardashians blasted Rob Kardashian for going MIA on them and Blac Chyna

Rob Kardashian went MIA on Sunday'sKeeping Up With the Kardashians. 

On tonight's episode, Rob disappeared on his family and Blac Chyna after the couple got into an argument. Everyone tried to get a hold of Rob on the show, but he blocked everyone so they couldn't contact him.

After Rob missed his grandmother M.J.'s birthday in San Diego, he resurfaced in Los Angeles. That's when Kim Kardashian, Khloe Kardashian and Kourtney Kardashianconfronted their brother and asked him where he went and why.

So where did Rob disappear to?

Take a look at the recap to find out and to see more OMG moments from this episode ofKUWTK!

1. North West Will Be Able to Read Music Before She Can Read the Alphabet:

While at lunch with her friend Larsa Pippen, Kim tells her about North West's violin lessons.

"She had her second violin lesson today, she loves it," Kim says. "She's like so obsessed."

Kim then tells Larsa that North's violin teacher said, "She's gonna learn to read music before she can read the alphabet."

2. Kardashians Want Lord Disick to Make a Comeback:

Scott Disick has been sad since Kourtney and their three kids went away on a summer vacation without him. So to cheer him up,Kris Jenner and Khloe decide to encourage him to bring back his hilarious alter ego, Lord Disick.

Watch the clip above to see if Scott's ready to become "the Lord" again!

3. Khloe Says Kardashians Are Forming a "Better Relationship" With Chyna:

Khloe and Rob are on FaceTime with Chyna when Khloe asks Chyna how to "isolate" her upper thighs and "make them wiggle."

Chyna tells Khloe to wiggle her legs and thigh muscles to make it happen. Khloe hilariously attempts to do it, but she's in jeans and it doesn't work.

After the LOL-worthy conversation with Chyna, Khloe says it's "really nice" that she and her sisters are forming a "better relationship" with Chyna.

"It's just good to have no bad energy or tension within the family and that everyone is just smooth and cordial and this is what family is," Khloe says.

4. Rob Disappears:

After Rob expresses that he doesn't feel "comfortable" enough with his weight to go to his grandmother M.J.'s birthday in San Diego, his sisters set up a stylist to come bring him options of clothes he can pick from. But even when he has clothing options, Rob admits he's still not comfortable.

Shortly after, rumors spread that Rob and Chyna have split, so Kim tries to call Rob but he doesn't answer. She then calls Chyna and Chyna explains that the two had an argument, but she thinks Rob is using that as an excuse to not go to M.J.'s birthday party.

Watch Kim talk to Chyna about Rob's behavior in the clip above!

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5. Rob Misses His Grandmother's Birthday Party:

Rob is still MIA when the Kardashians head down to San Diego for M.J.'s birthday.

"I mean I just think that Rob just has to start being honest," Kim says. "Enough with the excuses, like we're never gonna believe him. If he didn't want to come, just say, 'I don't wanna come.' That's what pisses me off so bad about him."

While Rob doesn't show up to the birthday party, Chyna still comes to make an effort for the both of them, which everyone appreciates.

6. Khloe & Kim Think Scott Is "Out of Control":

After hearing that the Kardashians wanted "Lord Disick" back, Scott flew to London to attend an airshow and considered buying a plane. He then charted a plane to San Diego from L.A. so he didn't have to sit in traffic.

When Khloe and Kim find out, they think he's gotten "out of control" and decide to crown him "Duke Disick" so he can create a new persona with a "clean slate." The girls then present him with the idea and Scott asks them what it really means.

Khloe explains, "We miss the Lord, that doesn't mean we need you to be like big ballin' and trying to buy planes. We just want you to be fun."

After hearing this, Scott agrees to calm down and just be himself from now on.

7. Khloe Blasts Rob for Disappearing:

When Khloe learns that Rob hasn't spoken to Chyna in five days, she tells Kim and Kourtney that they can't act like his behavior "isn't wrong."

Khloe tells her sisters that Rob is acting "crazy" and that his actions are "f--ked up!"

Take a look at the video above to see what else Khloe said about Rob!

8. Rob Reveals Where He Disappeared To:

When Rob resurfaces, Kim, Khloe and Kourtney sit down with their brother and confront him for disappearing on everyone.

"Of course now that we're back in L.A., Rob conveniently is found and answers his phone and unblocks all of us all of a sudden," Khloe says. "And you know it's ridiculous he keeps doing this disappearing act."

When asked why he disappeared, Rob explains, "I just didn't want to hear from everyone about anything regarding anything so I just choose to block everybody and that's it."

Rob then says he went to Las Vegas instead of going to M.J.'s birthday and while he doesn't think Vegas was more important than his grandmother's birthday, he didn't want to go to San Diego because he and Chyna got into a "little disagreement."

His sisters tell Rob he needs to "communicate more" and tell them when he's going through something so they can help him.

When they ask Rob how he and Chyna are now he says they're "all good" but they still "push each other's buttons" all the time.