Default [Q] Bizzare refusal for repair

Hi,
Just looking for some advice/insight please,
My 1.5yr old htc one x recently developed the dreaded 'blank screen of death', a fairly well known problem amongst htc one x owners, it can easily be googled or seen on youtube.
Its currently under contact from buymobiles.net, who i contacted, who then sent me an envelope for collection.
Upon the phones return, i received a tick box worksheet, indicating that the phone had not repaired, the box ticked was "fault not covered by warranty and the cost of repair exceeds the value". I would like to point out that there were boxes which could be ticked for things such as water damage, owner damage, previous repair, poor repair, etc. None of these were ticked, so obviously i phoned asking for an explanation, as to why it wouldnt be repaired. Person i spoke to agreed that this was strange, and would phone the repair centre and phone me straight back. Nothing, so next day phoned them back, I got a similair response, and was told that the original operator mustnt have been able to get through to the center and they would try now, they were unable to get through, and suggested they might not be back from their lunch break (although unlikely at 11pm!) and they would continue to try and would phone or email me later! Nothing! phoned again, only to be told servers had crashed and that contact with centre was via email and not phone, which i thought was a little strange after what i had previously been told! Again, nothing, phone again next day, operator agrees that it doesn't sound right and that phone should have been repaired, he phones the repair centre and then rings be back, claiming they wont repair it due to a "previous repair which had done been done badly". Now, as i pointed out to him, why would i pay to have my phone repaired when i can get it done for free under warranty? he agreed with me, and then suggested perhaps if i had broken screen and then had that repaired, thats a fair point but i havent. I asked for their response to be put in writing, and for photos of the supposed "repair" which he claimed they have. He was unable to elaborate on what exactly the repair was. I suggested that this indicates that i was given a refurbished phone instead of a new one when i first got it, he claimed that checking the imei number proved this was not the case!

I am still waiting for their evidence to come through! I spoke to htc who picked it up this morning for repair but i am concerned that they may refuse on grounds that buymobiles have been playing with it. Although the representative on the phone did admit that they have had a lot of problems with the htc one x. Part of me wonders if buymobiles even opened the phone up or had previous knowledge of the fault and decided they didnt want to pay for the phone. As i said before, the job sheet has a section concerning previous repair work and this has not been marked.

Any help or thoughts?