deducted money without memebrship

I joined your gym on the 11th of December,i live in Berea North and when i discovered that the gym is not in Hillbrow as i had assumed but in Braamfontein i sent and email to cancel this.I joined for me and my wife.Then 2 weeks ago i receive a call from gym company braamfontein alerting me that my tag is ready.I told them i had cancelled then she said i must come in person.When i get there she tells me i must pay R3500 to cancell both them tags.I told her i can not afford to pay this amount as i am currently under debt review.I have never taken no tag or been to the gym company.i dont even remember signing for a 3 year contract.