MTN selling customers private data

I app**** online for a cell phone contract with MTN giving my cellphone number and email. I was contacted by one of their consultants to go through the contract but eventually decided not to go through with it thanking them. Since the call my phone has had 4 spam/marketing calls from other companies. It has not been this bad before. This is too much of a coincidence. Is MTN selling people's private data???