The sentence "I open up their monthly"/the usage of "with"

Hi

Joey: Y'okay, Phoebe?

Phoebe: Yeah- no- I'm just- it's, I haven't worked- It's my bank.

Monica: What did they do to you?

Phoebe: It's nothing, it's just- Okay. I'm going through my mail, and I open up their monthly, you know, STATEMENT-

Ross: Easy.

Phoebe: - and there's five hundred extra dollars in my account.

.................

Monica: Alright. I'm gonna go change, I've got a date.

Rachel: This Alan again? How's it goin'?

Monica: 'S'going pretty good, y'know? It's nice, and, we're having fun.

Joey: So when do we get to meet the guy?

Monica: Let's see, today's Monday... Never.

All: Oh, come on! Come on!

Monica: No. Not after what happened with Steve.

I have two question about the dialogue stated above.

1- What does the sentence "I open up their monthly" mean?

2- What can be used instead of "with" in the last line? Is it something like what happened "about" Steve?

Thanks in advance.