Voltex does not want to refund me my balance

Good day

Please assist me get my refund from Voltex Pretoria North , firstly i went through hell just to change some items from Voltex Pretoria North now I am being played around when I request my refund , I submitted my new proof of account letter after I closed my credit card which i initially used to buy the items , now when the supposed to refund me they say I need to also write an email stating that i have changed my account, just now Soma Ayanda from Gezing is are requesting a collection receipt which they have a copy from their end please rescue me form this circus .