Data *****ing

Still waiting for consultant to contact me. Second request. My PC is protected by kaspersy 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. Thanks. Router/modum no is: ********** 570