Vodacom helping other persons de***** me and track my conversations

I am an international student with the University of Johannesburg. I registered for a vodacom SIM card number ********** 835 last year when l arrived in South Africa and subsequently used it to register my bank account details both here in south Africa and Ghana, my University contact, and scholarship contact details. Until now, l had been a regular customer with vodacom as l thought they were dependable and all my International calls were done and received through Vodacom. However, l had to travel back to Ghana for my field research between December 2018 and APRIL 2019. And l finally returned to SA in May 2019. When l returned, vodacom had deregistered me from my vodacom number and apparently given my number to someone else who at the moment is having access to all my WhatsApp conversations. Unfortunately, all my bank statements both in Ghana and here in SA and linked unto my vodacom number, meaning, this second person who is using my vodacom number is having access to all my bank statements and payslips. When l complained to vodacom, they told me it is their company policy that when your vodacom number is not active ( if you don't make calls, nor buy airtime) for more than 3 months, they will deregister you and sell off your number. Please am afraid of financial ***** now since its becoming difficult to change the vodacom number with all my banks and from my scholarship database. On the other hand my financial information are being released through vodacom to third parties without my concernt! I bought the SIM card and duly registered it with my passport. At least l should have been given warning notices on the new policy. Beside, vodacom has all my passport details and email, if they really cared about me, why didn't they notify me before deregistering my SIM. Now all messages from my banks, WhatsApp conversations with friends and family both here and in Ghana are being received by a third party without my concernt. My private life is no longer private because vodacom is helping another person to track all my conversations. Please l need my vodacom number back! Is there any help? My e-mail address; **********