Over charging on repairs which have not even been done. Now provider is refusing to refund me my full amount made as per Invoice.

I contacted T.M. Electronics cc - Springfield Park, Durban to repair my washing machine. I was sent a proforma invoice of R 1,345.20 which I paid them immediately. Two days later a Technician arrives to tell me that the part is wrong. Another three working days later I receive an email that I must now pay an additional R 1,076.60 more for the "other" part. I insisted on a refund as this is unnacceptable and ridiculous; only to receive a reply that they will only refund me for the part; resulting in me having now paid R439 for nothing - no service or repairs done! This is totally unacceptable service and is plain day light *******!