Contact Info Possibly sold??

I have a Sim with FNB. Its a fone my wife got me. The sim i use for Data but i never gave this number out to anyone and never registered this number ANYWHERE!!!...

Shockingly, i been recieving So much SPAM calls, Bot Calls, Sales calls to this number. Sometimes up to 5 per day.

FNB, How did this happen? Only way i can think is the contact details was SOLD??

How do all these Bot calls know of this number