Tranfered account

I took out a gym contract with Gym Company and after a few month I changed back to virgin as the Bromhof branch is badly maintained and managed. I then transferred the contract in Feb this year to my brother in law who extended it to 3 years. Since then I have had endless sms telling me my account is overdue and they are going hand me over. I have spoken to 4 different people who all say they will sort it out but never do.