Bad service regarding over the phone cel upgrade.

I had a call about four / five weeks ago and upgraded two of my mtn contracts... They promised that the phones will be delivered in 7-14 days... its week 5 now and everytime I call they have a different story... Or the delivery service could not get hold of me... (i havent recieved a call though) and now they don't have any stock? This is bad service and I am on the verge of canceling my contracts if they dont step up in the next few days!!!!