Firstly, avoid the need for users to contact support:
- Don't make breaking changes. (In the case at hand, the behavior of ⌘K was changed in a surprising and irritating way.)
- If you must make breaking changes:
- Announce them loudly. (You did not.)
- Provide an opt-out, or at least a carrot that's bigger than the stick. (You did neither.)
Secondly, make the "Contact us" easier to find: Don't make me jump through multiple links and support pages on the off chance that I'll find an existing answer to my question.