Don't ever take it in the shorts from any company, especially some small, crappy company like upgradeplanet.com
Dispute the charge...I think you 51 days to dispute the charge...if you paid with CC and can prove you don't have the device (i.e. a tracking number/delivery confirmation for your RMA) your guaranteed that you won't have to pay the charge and your CC will raise hell with them for bad business practices.
We as the consumers have a lot of financial rights that we do not exercise...call your CC and to dispute the charge. If you paid with AMEX then upgradeplanet.com will really be crapping bricks...I talked with someone who used to handle CS claims like this for AMEX and she said AMEX actually gets pissed and will file complaints w/ the Better Business Bureau, perform "random" audits of this company, and may even file charges of fraud against the company in some instances.
I like AMEX because businesses don't...and from the sutff above they have good reason. AMEX is customer centered...their customers are right until proven wrong. Mastercard seems to be getting better too... but I don't know.
Hope everthing turns out well for you!