Stalling: the majority of online casinos are guilty of it. Of course it's something they can just deny, and since some players get quick withdrawals, you will get mixed testimonies. Less likely to face this stalling bullshit when the amount is small, but still happens.
I've even had live chat pretending to have had connection issues and not responding for hours (conveniently when I brought up withdrawal after finishing wagering). Always super quick to respond about anything else, of course.