That's weird. I've never even heard of a glitch like that. Did you go to the website, log in there and check that all your details are still the same (banking, phone number, etc)?
One more thing to consider. Do you use the same password for anything else? Third parties often get hacked and those username and password lists are sold and then tried in various other places.
One more thing to consider. Do you use the same password for anything else? Third parties often get hacked and those username and password lists are sold and then tried in various other places.