Why is it taking so long to get my money back when you’ve recieved my faulty return weeks ago?

So unimpressed with ID mobile - phone was returned due to a fault, originally this was due to be a faulty exchange with a new handset sent out. ID mobile received the handset on the 1st December and since then I have contacted them numerous times only to be told I need confirmation from a warehouse team for this to be processed. At this point, I’m not even sure the warehouse team exist. I contacted ID mobile again for an update, at which point I was told the phone was out of stock until January (why you didn’t communicate this to me earlier I don’t know). From here, I requested a refund as I was not willing to wait until January paying for a phone that I didn’t have. The chat agent confirmed that the refund would be processed for the upfront cost and she would also request a refund for what had been paid so far. This was last Saturday, and nothing has happened since. Today I contacted your live chat agents again for them to say that this refund isn’t even down as being processed and this will only be done when an investigation is carried out by your complaints team and the warehouse team have confirmed receipt. I sent the phone back to you tracked 48, I have proof that this was received on the 1st December and you’re now withholding my money, making me pay for a contract on a phone I don’t have all because someone in your warehouse can’t be bothered to check and confirm receipt. Shocking that your chat agents might as well be bots as they have no want or desire to really help, they simply say that they’re unable to check with the warehouse team - again, suggesting that they don’t even exist.

Shocked that such a large company can provide such poor service and withhold customers money.

Under the Consumer Rights Act I was well within the timeframe to return faulty goods, and under said act a full refund should be supplied.

I have contacted your live chat team, previously posted on the forum and had a conversation with someone and no one has so far resolved the issue, I am willing to take this further to Trading Standards if needs be.