Giving a balance of arrears with no explanation!!

My Fiance canceled her subscription last year September and it was only finalized in October. She then try opening a new subscription this month after paying her activation I then got a call saying that her account is 2k in arrears. We spent the whole day yesterday finding out why as no one is able to tell us why its in arrears. Her 1st contract started in 2021 and was a 12 month contract, in 2022 it moved over to a month to month contract. Why must she pay 2k if no one is able to provide us with a reason for this balance on her account. As far as any other company when it comes to month to month if you don't pay they cut you off there are no penalties for that but not this greedy mf company. On the day she canceled her subscription there was no mention of any fees that will take place. So please tell me why? We refuse to pay a balance if no one can tell us why or for what. Most greedy and useless company I've ever seen. Shout out to the sales consultant that did his best to help us but F*ck planet fitness!