I use AT&T Landline service and I just got a call from the (506) 226-8917 number with an offer to "lower my Visa or Mastercard interest rates". I pressed 1 to talk with a rep and then I've asked him what bank he is representing and then the "fishy" part he  reply that is representing "VISA and Mastercard" and not a bank and they could my interest rate. I said I do not need carry a balance and he hung up. This number shows from being from Costa Rica.