Refusal to cancel my contract while I never used their services

2021 November just after my work contract expired, I received a call being told I’ve won a voucher for a holiday and I should come to Pretoria to fetch it in person. When I got there the reception desk asked if I’m working I said no and she said I should lie to them that I’ve got an income so that I can get my voucher and I went through the presentation I was channelled to join or rather purchase one of their holiday packages to go for holidays anytime I want even abroad, however if I can’t afford to buy it cash I can pay minimum amount and I did that. While I was paying being told to do internet banking with their laptop that’s when I began to be sceptical I refused n used eft. Two months later I realised I can afford to travel without them and I stop sending them money and they refused to cancel my contract telling me I should pay for 15 years. They are a **** don’t fall for this