Wrong brand sent, I returned the wrong part to onlinecar parts. 7 months later still no refund, irregardless of numerous follow ups made with different staff members

I bought the Mercedes C220 W204 CDi Glow Plug 2007- (Eng. Code OM646.811) NGK - CZ106, on the 03/09/2024. Through online services. I had to make numerous follow ups with the guy Named "Nesh". According to him they did not have it in store. At some point he called and said he got it from the other, I confirmed with him it NGK and said yes. He couriered the glow plugs and upon receiving them it was not the NGK brand. I communicated with with him then we agreed that I must return them back. I couriered them back on the 20/09/2024. On the 25/09/24. He confirmed he got them, he'll then speak to his finance department and start the process of refunding me. Till today I haven't received my R2 600.00. I have made numerous follow up with different people from this shop, no success. Vanessa Naiden (+***0), Xoli and Aprina (+***5) to name the few that I have spoken to and they'll all promise to assist eventually they will ignore my calls. I'm really disappointed by their conduct. Seven months later I haven't received my refund of R2 600.00 including the R141.00 for courier services for the return. 19/04/2025.