Air Conditioning - Defrost Inside Coil

I stupidly forgot to change the air filter in my new A/C system, and called out a professional. The major charge on the bill was $90.00 for "Defrost Inside Coil". I don't take issue with the fact that the inside coil was frozen, but it seems like this would be something that would work itself out. When asked about this, they said that if left on it's own, it might have caused water damage while defrosting. Does this sound reasonable?

Absolutely Maybe Sometimes well shoot techs have to eat and they do like brand name beer and cigs not generic so pay up. Whenever I do something that ends up costing me money for nothing I just call it a learning tax (stupid tax if done twice)

That $90 bucks is just a standard service call charge. What they had to do was not covered under the warranty, so yes they did right no matter how he worded it.

Killians is $6 bucks a six pack.

Thanks, I still feel a little dumb, but not dumb and overcharged.