Gym company payment

I had a contract with gym company which was coming to an end in April so today I went there to pay and cancel my contact but could not, they say I have to pay for both June and July because their system is ready for July payment and I feel I am being ****** here because today is the 23rd. So I want to know if this is acceptable, please help me in this regard.

Thank you Busi Khawula.