Terrible customer service!!!

I ordered a pair of shoes and it arrived in a decent amount of time. The shoes were too big and that is where the problems started. There is no return order form or anything, you send a mail and they just send you the return address. I returned the shoes, emailed the tracking number and requested that they send me a smaller size. 3 weeks later they still haven't collected the shoes after I emailed them twice saying the shoes are at the post office - no response from their side. I tried phoning a few times, but they just don't answer the phone. I then contacted them via Facebook messenger to which they said that the new stock will arrive within 2 weeks. It has been more than 2 weeks and I still haven't received the shoes and the Post Office sent back the original pair as they never collected it. Their customer service is pathetic to say the least and it is such a shame as they really have a good product with great potential.