Data charges and Outgoing calls

I ported my number to mtn on the 20th of October, i am however unable to call 173. I also struggle with making outgoing calls as it informs me I do not have airtime, when I actually do have it. My data charges are ridiculous.<br> Each time I call the help line i get transferred to diff departments and do not get help. I'm tired of calling in. when I go inside a store they are unable to assist and advise me to call 173 which I cannot call using my number and have to ask someone else each time.<br> I regret porting my number as mtn has not been helpful