Caller ID shows S-H AST

Barely 9 a.m.   Call went to recorder.  No message left.

Caller ID said Toronto ONT.  I know no one in Toronto ONT and did not answer as a matter of policy.

Got a call from this number. I pressed 'zero' and got an east indian guy who wanted to sell me some kind of credit service. I told him to take me off his list. He told me how much credit card debt I had. I told him that it was none of his business and to take me off the calling list. He said he would but I'd have to stay on the line. That didn't sound right so I hung up. I googled the number and it is a land line in Toronto, Ontario, Canada. The number is registered to company named S&H associates. How the hell do they come up with my credit card balances?