Dell Charging My Debit Card, #2

I found a miscellaneous debit of "POS DEBIT DMI* DELL SALES & SERV ROUND ROCK TX",and deducted $1687.55. I don't buy anything on the net, just register an account. when I search the item by my name or phone number or zip cord ，I have found nothing，I want to know if this is your account and what I should to do？ 

Thank  you!