I am a complete newbie with online wagering, however I am able to competently place a wager and read a screen.
I decided to bet the NCAA tourney games this year (big mistake based on my P/L so far).
Looking at the reviews here I chose 5Dimes as my sportsbook.
After a Day 1 with no issues, one of my wagers today was modified after being submitted. The amount of the change is quite small, but the point is 5Dimes changed the wager themselves. After submitting wagers 5Dimes has a page which allows you to view pending wagers. I placed wagers on the first 3 early games in the tourney today and then went and verified them on the Pending Wager screen. All looked OK.
I came back about 90 minutes later to wager on the next round of games and found one of the wagers had changed in amount. Again, the change was only about 10% of the original wager, but it was changed.
I contacted 5Dimes via chat and phone and in both cases was told nothing could be done.
I'll be finding a new book and thought I'd leave the info here.
Spektre