Pathetic, Appalling service

I was at Virgin Active today to join as new member. I was previously a member from 30.04.2014- 31.07.2015. Today i was helped by Themba who informed me that there is an outstanding amount of R800 since 2009. I was not aware of any amount owing by me to Virgin active as in the last 6 years i did not receive any correspondence regarding this and upon joining in 2014 i was not informed of this. I was told this after the payment for joining and card fee was taken and now my sister who made the payment has to wait to be refunded for the payment. I was told by Themba that i will not be allowed to join the gym and he would only assist me if i pay 50% of the outstanding amount. I am fully aware of my consumer rights and since i was not aware of owing Virgin Active any money since 2009, this so called outstanding amount should now be prescribed according to The Prescription Act 68 of 1969. I will be seeking Further advice with regards to this. If any outstanding amount was a problem, why was it not brought to my attention before? How did the Consultant at Boulders allow me to join in 2014 without this being an issue. Customer service is appalling, pathetic and useless.