Turning customers away

MTN has been pressing me weekly to upgrade my contract, today I decided to do so, I responded via the email and no1 called me back. I walked into your store at Fourways mall at 17.45 only to be told by Clementine that I must come another day as they are closing shortly??? Really to upgrade a contract which takes less than 10 minutes? Also you turn customers away because you closing in 15 minutes? If thats the case why is the doors still open at that time? This lady was rude and didn't care to assist me, a customer for over 14 years!!!! Absolutely pathetic service, go view your footage