please read this with details

I bought an HCT sensation and after use of 10 days, much dust started to be on display, and I gave service that is Teleservice, also I desired to get money back, because this is my right, laws give this right to me in TURKEY, so they do not want to give my money back and they gave me HTC sensation XE with respect to their saying, that is pleasing for customer, and also I didnt admit then I resent smartphone which was dado to me (HTC sensation XE) but I must say that The phone dado is not in original box and accessories, with old things was dado only thing changed is the phone however tu cannot understand whether the phone is original o not cloned, there is no any sign about this phone is original, and the service defines in reportar that the cover is changed and battery also is changed, so how can I know this phone is original and why not this phone is dado original box as tu know Sensation XE has beats audio headphone, this application is not applicable, who can admit like this behaviour ? last thing is that Sensation Xe also has some dust and boiling when running.???