Wait a minute here. Are you telling us that you swapped out or use bulbs that are not compatible with dimmers but changed out all switched so you can use those bulbs and charged the owner for the work?

Who put the "corkscrew" bulbs in, you or the homeowner?

^I would be pissed if my tenant did that and charge me for it. It must be an older building and the lighting were made for pre-corkscrew garbage. I would expect my tenants to use the correct bulbs and not change out switches and bill me for it. I understand the switch isn't working and get that changeout but all of them?

^^
No way in h e l l would they bill me for it. As soon as I learned of this I would have an electrician put the correct switches back in and bill the tenant for it. I would also tell the tenant that if he starts doing electrical, plumbing, or mechanical work on my property that he is not licensed to do I'll evict him. I don't want some amateur burning down my investment.

Wait ...

You billed the home owner $200 for a job you had to come to PPOT to learn how to do?

agreed

Sound like wrong bulb was used