Should providers tell clients that they are having their period before meeting the client? I recently met a provider that didn't tell me until I had paid her. I felt cheated.

If you didn't want to go through with the session, you should have told her and asked for most or all of your money back.  I don't know how long she waited to tell you, but I can see how even ethical providers would have trouble blurting out something like that, especially if you had just met.

If you went through with the session after she told you, well, you paid for services you received, even if it wasn't what you had anticipated.

But, yes, a professional, ethical provider should have told you before accepting your money.

can be pretty ugly.  IMHO, not worth it.

Sorry, dude, she took your hard earned $$$$.  Just don't see her again unless she makes it up to you w/ some compensatory time.

Some guys like a lot of lady to guy oral and/or a Russian finish.  Same guys sometimes have trouble finishing with a cover.  YMMV