We get one of these "Rewards Redemption" calls within 2-10 days of adding new minutes to our pre-paid cells, EACH & EVERY TIME. Just added minutes a week ago. So, that means either NET10 OR CALLINGMART.COM, where we buy our Net10 minutes at a discount is the culprit. Neither entity has nor will be privy to our credit card number as we always use PayPal for these transactions. But they keep trying via these SPAM calls to get it, without fail. I have turned them into the government more than once, but nothing happens. Got one today while we were at an open house tour!
Oh, and the one ring call is a TRAP. If you call back 'out of curiosity' they will capture your number and then can use it to 'prove' you've "established a business relationship" with them - which makes all their spam calls after that 'legal.' You would not have a 'claim' against them - if it ever evolves to that - for harassing calls in that case.