Disloyal customer service

i really don't understand what i have done wrong here. since 2020 i have been pleading to get good customer service from your company, still nothing. i have not once lost my temper or disrespected any of your employees in any manner.

i paid R2500 for an intake manifold, waited months just to get it, and finally when i get it turns out to be the wrong part. i return the part back to you and in the hopes of getting the correct one, to no prevail I then ask Theo (sale agent) of a different part instead. Just getting a response regarding the alternative part took 2 weeks. At this point I had to accept that i wont get parts from this company, and was left with no choice but to ask for a refund. it has now been 2 months and 2 weeks since i asked for the refund. i call and call and call Theo, only to get empty promises on when the refund will be paid. On Monday 10/05/2021 i spoke to the manager and she assured me that the refund will be processed on Friday. Till today, still no refund or any communication given.