Watch your card accounts very close

This is a warning to all of you,and hope this isn't happing to you.Just today i logged onto citibank's website to moniter my account,and to my surprise i see a charge that i don't recongize,the charge was for $226.00 from a company named the conference exchange out of cumberland rhode island.So i wasted no time and called citibank right away,and informed them that i didn't make that transaction with this company.I asked citibank who is this,and they told me it is some kind of professional service.Does anyone know anything about this company?It looks like someone has stolen my credit card number but i don't know how in the hell that they can get it when i have my card in my possession,and i didn't call anyone,nor did i make the charge with this so called company.So citibank is going to send me a form out within 10 days disputing this charge,and they are going to credit back my account in the amount of charge that i didn't make.I hope they get this settled pretty quick,and fairly.I don't even use my citibank card,and can't figure out how someone would get my card number.Does any of you have a clue how a theif can get a card account number with out me giving it out?Has someone possiby hacked my computer?This is the very first time that somthing like this has happened to me,and i just wanted to give warning to you all,so that nothing like this is happening with you.