no bbc chanels on my samsung?

i cannot get any bbc chanels on my samsung tv.Everything was perfect on the original digital switchover,but since having to do a final retune all bbc chanels have gone.Digital uk tell us our reception is good ,all our neighbours get all chanels.Samsung tell us it cannot be the tv and we should try putting it up stairs?We have tried getting the tv back to factory settings but no go.HELP please.....