Personally I think:

When having a car mapped you are paying for the mappers expertise, knowledge and time.

I would not expect an unlock code, and if you are unpleased with their work why would you want to continue using their map? (obviously due to cost but if it was not happy with one part of the mapping I'd want it all re done by somebody else!)

I think if good relations however are kept with you and your mapper they would do things to help in times of problems, however this is obviously not the case here!