Airtime ******* By Vodacom

Not so long ago I did a sim swap and had no problems with my previous simcard but now that I have a new simcard all of a sudden I'm loosing airtime with no reason at all and when I call Vodacom the is no one to take my call,now I am afraid to buy airtime this is not fair and it's a very terrible experience I have ever experienced with a service provider Vodacom is a very very very bad company.