Purchase 2020 (short delivery) refund still pending, bad customer service

I made an online purchase to TGFG on 30th of Dec 2020, the item i had purchased was sold out, which i only knew about when my order was delivered, and inquired as my items were short, Since December 2020 I have been asking for my R599 refund, have sent more than 10 emails and all i get is we will process. i have phoned being transferred from one Agent to another even the supervisor, i have sent a bank statement thrice, not sure what else to do,