I don't have a prepaid ANYTHING. And definately NOT a prepaid phone & I've been getting calls from this number. I totally agree this is some scam or something, but think you may be barking up wrong tree. Hope you figure it out and get it resolved.
This is an unbroken pattern of at least 4-5 years; we have to put minutes on every 3 months, on two different phones, so I'm pretty confident in my suspicions. The spam comes in anywhere from a few hours to up to two weeks (but no longer) after we add the minutes using the pin provided in each transaction. Only one, per transaction, thankfully. They don't seem to sell or trade beyond that one attempt each time. We believe CALLINGMART is an overseas company; likely India. They don't play by the USA's rules. (Although, I'm SURE there is some FILTHY rich American ownership connected to them.)
Perhaps you do business with an 'affiliated' company or website to CALLINGMART, and just don't realize it???
They call and hang up before I can answer. They leave no voicemail. So I don't know who they are or what they want. I want them to stop calling. Thanks.