Fitness Connection Hard to cancel membership they even gave me wrong p.o. box to mail cancelation letter which I paid to mail certified. houston, Texas

I was given wrong info with regards to canceling my membership by my club front desk.  I was told by my bank with fitness companies they recommend changing debit card because they have  had past problems.  About three months later I get a call from Fitness Connection threatening to send my account to collections.  I was told I needed to send a letter to corporate and would be canceled within thirty days then I was given a wrong P.O. box that I mailed a certified letter to just to have it come back undelivered.  I feel they do this with a purpose to extend the length of time it takes to quit. I just don't understand why else the front desk would not know the process.  When the first payment got rejected because the debit card was not valid why would they continue to submit it over and over for three months before they called did they think the card took a vacation and would soon return I just don't get it they are not being fair and want me to pay for all the return charges.  They will not even send me a bill in writing.  All I can say is go to Planet Fitness.