WORST SERVICE EVER!!!!

Very seldom do I get so annoyed that I feel like screaming at someone, but Groupon service staff has tested my limits beyond reason!!<br> <br> They blocked my account saying that some payment that I have done has been reversed at the request of my bank, and therefore I owe them money! Now here is the fun part: I have made no purchases in the last 1 month! So the first thing I thought is, that someone committed ***** against me!<br> <br> I have to call them (by now I have called them on 5 different occasions to get to the bottom of this) and they tell me they cannot give me the number of the transaction, the amount or even the date! All they know is something was reversed and because of it, I was blocked! They don't know what I owe! For what I owe! Or why I owe! They only know that I owe!!!<br> <br> I spoke with my bank, and nothing has been reversed! But to investigate this further the bank needs either: an amount