I want my refund!

I've been asking for a refund from Netvendor due to a problem that arose during the previous weekend, I was told to send an email with a proof of purchase as well as as my meter number then I was asked to confirm my banking details of which I did and I haven't heard from Netvendor since. I even sent 2 additional emails and I didn't get any feedback, tried to call them as well but I was left on hold for more than 30 minutes.

Meter number: ***3