I need to get a conversation when a contract was done for a lawsuit. I would be filing.

Conversation is around two hours long. I was promised something in the phone call for the new two-year contract and am not receiving it. I was promised to Sim cards in my phone. My phone that I have already does not even charge, why would I want it to 2 year contract? I’ve asked multiple times for a supervisor to listen to just the last 30 minutes of the phone call when I was promised this multiple multiple multiple times even saying myself this deals too good to be true. Called me back without listening to the phone call, said they would listen to the phone call and call me back. It is now been three weeks tomorrow! This was on March 3 when the payment went through. What do I need to do to get the conversation, I am representing myself, do I need to get it subpoenaed? Thank you please let me know. Hopefully, this will not take 20 days as a supervisor has still not called me back from this entity.