Bad service

I have a problem with sbk gym ,i joined the gym some time last year i went two times so it happened that i dont pay them for that one month cause i had financial difficulties,en i wanted to start gyming again the said no my account is already with the attonerneys now they saying im owing them 8000 bt its not fair to pay that amount while not allowing someone to pay and come back to the gym cos ma contract with them is not finished