Support Sim locked?

Hi

I bought an 'unlocked' HTC one sv lte from a shop in ebay (I put in a bid not expecting to win, but got lucky I guess) and a sim card from 3, however when I put the sim in it told me that it was network locked, with a space to put in a code. I have been trawling the internets but cannot find out how to unlock this phone. I cannot get a code as I do not know who the network operator is supposed to be. I checked that it was not blacklisted, but have come to an end in my abilities to solve this. Any help would be appreciated.

DrBoloid

 

Thanks for the replies and suggestions everybody.
I have contacted the vendor on ebay, and they told me that they won the phone in a competition, so I have made some enquiries about that which may help. It came still sealed in the original cellophane wrapping so unless someone went to a lot of trouble to reseal it, I believe it was brand new. I also checked the imei number and it does not come up as blocked. So I guess I will just have to wait and find out more if I can.

 

After doing a little more research it seems like the only network in the uk selling this phone is EE, and their website says they want

 

I have just ordered a T-mobile and Virgin sim in the hopes I can track down the provider, Virgin actually have an OK deal so if it is locked to them I may be quite happy to leave it locked. T-mobile is not so good and EE prices are pretty high for very small amounts of data used.

 

Can I say thanks to everybody for your input.
The ebay seller got back to me and explained a bit more about the phones origins, and we worked out it was probably locked to EE even though this was never made explicit to them. To be fair they were very good and offered to contact EE for me. However the virgin sim arrived today and worked without any problems. The deal I have with them is OK, 3gb and unlimited txts free when I top up