TERRIBLE CUSTOMER SERVICE - SOLD ADDITIONAL SIM CARD THAR DOESNT WORK FOR IPHONE 11

I was sold an additional Sim data card and told by the agent that my iPhone 11 takes 2 SIM cards. It does not. I have tried to cancel the contract but they won’t let me and say they need to listen to the conversation first. I logged this cancellation on the 20 June. I have tried calling numerous times with the promise that they will listen to the call to see what the agent told me. Nothing has happened. No one has gotten back to me