EXTREMELY POOR SERVICE/COMMUNICATION!!!!!!!!!!!

On Thursday 4 February I received an e-mail saying my Mastercard was in arrears. This after I paid in full on the 1st and received an SMS confirming it – the full payment also reflected on my statement. I immediately called Mastercard to find out what was going on. After a very frustrating conversation I asked to speak to a supervisor. After being put on hold for 7+ minutes I ended the call. I did receive a call to say a supervisor would call me later in the day…..now 4 days later STILL NO CALL! I also sent an e-mail, the same day, requesting an explanation but also STILL NON REPLY – not even an acknowledgement. I have been a Mastercard holder since 1974 and this is the 1st time I received a notification I'm in arrears!!!!!!!!!!!!!!!