Makro on line

I ordered an Inverter on line and it was delivered on the 16 Dec, unfortunately it did not work the green light did not come on, so I immediately informed them and requested a refund. I have a ref no; ***9 regarding the refund. I am still waiting for them to collect it and refund me !!!! I ended up going into Makro Nelspruit to complain , they were fairly helpful and said they would escalated my request, However apparently a 3rd party is involved, (The Market place)so they cannot help, which I think is unacceptable !!!!!!As it was Makro's website site.