ups lost my package - tmobile wont refund me

My T-Mobile package was undeliverable so it was sent back to T-Mobile. Ups lost the package in the mail so T-Mobile filled a claim with them. Ups sent the claim to T-Mobile but T-Mobile has not done anything about it and do not want to refund my phone until they receive the phone. But the phone was lost in the mail. It's been over a month and I have not received a refund. I call T-Mobile and they keep saying 5-7 business days that they are escalating my claim but I called back today and they said a claim was never put it. I don't know what to do anymore. I just want my refund.