WORST CUSTOMER SERVICE EVER!

I have completed an order online on 27 April 2023, of which was meant to have been a "Sun DC to AC Inverter" and a "AxTech Lithium Ion Battery". I received the wrong brand in terms of the inverter and decided to return both items, of which was both collected. On 08 May 2023 I was refunded for the inverter, and ever since I have not received the refund for the battery. I have called twice prior to today and I was told that the relevant department (Marketplace - they deal with 3rd party sellers) was on both occasions notified and awaiting feedback from the seller. I decided to call yet again today seeing that no one has decided to keep me as the customer in the loop with ANY FEEDBACK with regards to my money that I am waiting for. The 1st customer service agent placed me on hold for nearly 5 minutes after explaining the issue. I ended the call and so behold I yet again explained myself to simply be told that I will get a call back but Siya stated when I asked when that he's not sure... I then asked for a manager or team leader and yet again was I placed on hold for 5 minutes. I called back and yet again explained my issue and asked for a manager or team leader AND YET AGAIN PLACED ON HOLD FOR 5 MINUTES and I ended the call. I have emailed without any reply, I called numerous times without any solutions and everytime I ended the call I actually expected to be called back but NO!