A very disappointed Customer

I was approached by a sales consulted at Balfour park mall to join virgin active ,he told me about the promotion that was going on and he said i need to pay 100.00 to join which i did he then took my banking details.I asked about the cancellation fee and since there was no contract to sign or a copy of a contract given to me i asked questions about cancellation fee and he failed to give me the correct answer. Today i spoke to a consultant asking about the cancellation fee and she told me a huge amount that i need to pay.please advise how to deal with this matter as im not prepared to pay to pay a percentage i didn't not agree to pay