Data *****ing and rotten service

This is my third attempt to sort out a simple problem No promised phone call or email I’ve a suspicion that my data is being ****** since I received a new modem after replacing my faulty modem. My Vodacom contract gives me 2Gig data per month. My data was finished halfway through Dec 2017. I purchased 500 megs on 16 Dec 2017. It lasted about 3 days. I purchased 1Gig on 20 Dec 2017 and hardy used my pc. Today, 31 Dec 2017 I tried to download a file of 48 megs. Suddenly I received a message that my data was finished. The consultant at Heidelberg mall was not very helpful to sort out my problem. I also do not get messages warning me about my data use. I’ve had this contract for more than 2 years and never had problems like this before. Kindly investigate and advise. NBRouter/modum no is: ********** 570 It could be an ******* sim swop. Surely Vodacom can see where all the data has gone. I haven’t use my modem since 31 Dec 2017 Vodacom’s automatic common answer “ we apologize for the inconvenience bla bla bla and a consultant will call you bla bla bla or I’ll send you an email bal bla bla.