The advertised a rate then added "resort fees" on checkout - I believe they have been ordered to reimburse their customers for the "resort fee".
The problem sounds like they added it at check out so it was a hidden fee. The fees must be explained upon check-in.
I don't like them just like I don't like fuel surcharges or mandatory options. Just a way to lower the price or weight for advertising purposes. I avoid those places because if they aren't being upfront with the price, I wounder how else the are cheating their customers.