I think Rin's idea of their "contract" was so different than what she expected to the point where she didn't know what to say at certain moments. And even now she's still doing that because INSTEAD OF BEING HONEST, MS. GURL CHOSE THE MOST SHALLOW THING TO SAY to Momoka and it's most definitely what she didn't want to hear from her.

Overall, kinda mad at Rin rn for expecting Momoka to just take her back after that kind of reasoning. I'm sure she'll later understand why what she did was wrong but who knows? ¯_(ツ)_/¯

Momoka goes about things in a trash way so her expecting her to understand where shes coming from is her just reaching tbh. If she talked up more instead of just expecting “this is how it should play it” then they wouldn't be in this problem