Hi Demeris,
Welcome to the QVC forums. You are a new customer, but I am a very veteran customer, and I am having the EXACT same experience as you-- I mailed a return March 2nd and there has still not been any movement.
Hopefully you used the QVC return label, because once you drop the package off, the responsibility is on USPS and QVC--not you. QVC pays for full item insurance with their labels.
I think some companies like QVC use the lowest level postage available, and they subcontract with a shipping agent, and of course there are a lot of postal delays, so it is all creating a lot of chaos. The tracking numbers are not always updated, either.
You can contact QVC customer service through the moderators of this forum--qvcsocialteam@qvc.com with your order number, and ask them to watch out for the return.
You should be able to request a refund even if the package does not arrive in the 30 days as long as you can demonstrate that you mailed it back within the timeline, and the delays are beyond your control.
If you did not use the label, then you need to have your USPS receipt and continue with your efforts for the "lost" package, but still let the QVC team know.