Hacked

Good day. On the 15th of July I had contacted Vodacom customer care line regarding a slow internet connection that I was experiencing. At the time I was on call with one of the operators I noticed that a sim swap was done on the cell number that I was enquiring about, at the time I presumed that it was because they had reset the network to help me with the internet connection. It was the next morning when I realised that a sim swap was actually done on my phone number, so I called back vodacom to reverse it however the who did the sim swap person had already accessed my WhatsApp. The person went on to contact my close friends asking for money pretending to be me. I believe the person behind this hacking is one of the employees at vodacom that I spoke to on the 15th. How can I resolve this?