Sorry if this is in the wrong section and sorry if this question has already been asked.
I recently purchased a second hand SGS2 from CeX, I attempted to update it to the latest software and failed. Then after days of Googling, I found out that it's actually rooted. It doesn't connect to Kies either, but I'm assuming that's a separate problem.
I joined this forum as a last resort because it is starting to frustrate me a little, I'm not good with things like this. Is there any way I can unroot it at all? Or, is there any way I can update the phone without unrooting it?
Should I just take it back to the store and explain the situation to them? Although, they might think that I've rooted the phone and then I won't have a leg to stand on as I have no proof that I purchased it rooted.