I feel I'm being taken for a ride

Hi, my name is Martin. I joined body life gym in 2014 for a year contract and was paying R299. Halfway through my contract I had to leave the area and asked to cancel but denied.

I left the contract unpaid for some time and now I called as I found out I had a judgement on it. They sent me invoice and I promised to pay in full as they also promised to give me paid up letter. The amount was R1644. When I'm busy requesting the letter they then deny and say I must pay legal fees of R4500.00. This doesn't make any sense to me