Who called from 5206649698

I have never been home when they have called.  Never leave a message.  I tried calling the number and a recorded voice says the number is no longer in service or disconnected.  Who are they?

Did a reverse telephone number search and it indicated that it was a residential telephone number. My guess is it isn't.  Telemarketeer for sure.

They have been calling me like crazy for the past week or two. One time when I did pick up, the first thing the guy said was "This is not a sales call...) so i hung up.

Probably CITIBANK or CITIGROUP.
They took over SEARS CARD accounts
and I have billing dispute with Sears.

I get this same phone call SEVERAL times a day, with variations of this number.  Others:  520-662-8999/8998  When I pick up, they just hang up.  But, I can tell there is a person there.  WTH?