Went to a Toyota dealer for an oil change and they seem to have messed up my AC controls perhaps when resetting the oil warning.

The car used to maintain the previous setting when turned on. Now its off and preset to 75. Any suggestions?

 

Did they change/clean the cabin filter............................................

 

NO, they did change the engine air filters. They may have checked the cabin filter

 

I agree that should be the problem.
If cabin filter is not in all the way. That will cause the same problem.