800-309-5501

The number is Credit One Bank.

They keep calling i never had a credit one card so im surprised to read here that its a debt collector for credit one.

That post was made 8 years ago.  If the caller is actually Credit One Bank, then it is not a debt collector as defined by federal law.  It is an original creditor.  It is possible someone owes them money and had your phone number previously.  I would take the time to identify that it really is Credit One Bank and then send them a certified, return receipt "not me" letter.

This is the MasterCard Fraud Detection Department.  They will call if an anomalous charge is detected and will ask for verification that you or someone you authorized had made the charge.  It is an automated call.  If you do not agree the charge was made by you, or if you hang up, the system will automatically assume a fraudulent charge has been made and stop charges made on the card or cancel the card entirely.  This may or may not be a good thing for you, since you will then have to go through the process of reactivating your card or, worst case, get a new card.