How to lose loyal customers by spamming them ceaselessly...

So I cancelled my Vodacom contract a few weeks back because I didn't need all those minutes anymore. I was planning on just buying pay-as-you-go as and when I needed airtime. I confirmed with the cancellation agent that I would keep my number (even recorded the call with this built in android app). Lo and behold the number gets cancelled too. After a call to the cancellations department I get my number restored. This however is not the reason for my complaint.

Within days after my cancellation, I get a call (which is blocked by TrueCaller as spam) from Vodacom, then another one from Mondo Vodacom (a third party contract seller I think, also blocked by TrueCaller)

Between the two numbers they've called me 34 times in 1 month, sometimes 4 times in one day. You'd think that the system would eventually see that it's not getting through to me, but NO! The calls keep coming, and coming. Please Vodacom, take me off your call list! I'll come into a branch if I need another phone or contract. This is ridiculous! This is how you lose loyal customers.