Best Buy Credit Card Bill Pay by Phone. The company maintains an automated system over the phone, which you can use to pay your Best Buy card bill. Contact Best Buy customer service free number 1 888 574 1301 available 9AM-9PM Monday-Friday, 8AM-8PM Saturday and 8AM-6PM Sunday. Just follow the instructions in the automated phone system, and pay Security assessment for Best Buy bill pay page has been provided by Symantec's automated analysis system. Check Best Buy bill payment page for malware, out-of-date software & against major black lists. By authorizing Online Bill Pay, I authorize Citibank, N.A. to initiate an electronic payment from my bank account and I authorize my bank to honor the withdrawal. This authority is for the My Best Buy® Credit Card account noted above and is to remain in effect until canceled in writing by Citibank, N.A., my financial institution, or me.