Sounds like they are making it up to me - if the timing is out it is because they haven't but the belt back on properly. Dont pay a penny in my opinion - its their job to do it right in the first place.
I would get a secong opinion on the cause and remedy, then tell them you've just had the cambelt done, and if that could be the cause.
I would get a secong opinion on the cause and remedy, then tell them you've just had the cambelt done, and if that could be the cause.