Asos Return Policy Issue - 4-Month Wait for Refund

I purchased a couple of tracksuits from ASOS through their online platform and made the payment upon delivery. Unfortunately, I ended up receiving four different items of poor quality. I returned them and it's been four months, but I'm still waiting for a response. Despite their apparent high quality, they fail to answer the phone. I've escalated this issue to the Consumer Arbitration Board, and if their response is unsatisfactory, I'm prepared to pursue legal action.