Late Delivery and Service not activated

Got called for an offer for 2 sim cards, one with 2 gig data, and one with free minutes. Delivery only happened three weeks later only, and my service was supposed to be activated within 48 hours of the tablet and sim cards being delivered to me. It is now almost two weeks after delivery, and I can not get through to the call centre (Keeps ringing for 25 - 30 minutes whereafter I end the call) to activate the service, as I have already received my first statement, but no service whatsoever other. Please get this sorted ASAP as I will refuse to make any payments if I am not even receiving the services I am being charged for.