home Internet device return fee

Back in May I signed up with T-Mobile and utilized their free trial for the home Internet device kit. After coming to the conclusion that it just wasn't for me, I returned the device via UPS in June. My December bill showed a non-device return fee and now my bill is over $500, UPS takes seven days to ship from Idaho to Texas, so why did T-Mobile take six months to notify me that the device wasn't return to them? On T-Mobile's webpage, it states that after 30 days if the device isn't returned, the fee will be applied to the bill had T-Mobile followed their own policy. I would've been able to track it down with UPS but because UPS deletes tracking information after 120 days, T-Mobile says I have to pay the bill, after countless phone calls with T-Mobile representatives, they all told me I needed to call UPS after calling UPS, they told me that because I didn't on the device and it was rented to me T-Mobile needed to contact them. So I called T-Mobile back and they told me the same thing that I needed to contact UPS , it's obvious that this device was either lost or stolen in transit, which is not my fault. I will not be paying this bill. Normally I would give the company the benefit of the doubt but because T-Mobile has now been  hacked twice within two years, I am convinced that this company is unprofessional, rude, inconsiderate  And inept. T-Mobile can take me to collections and I will follow Acacian if I have to because I was the only person who followed procedure and followed contractual obligations and yet I'm the one who's getting screwed shame on you T-Mobile. I was a completely satisfied customer but now because of this event, I, my brother, my mom and my dad and my sister-in-law are all canceling our accounts .