Who called from 2089687156

It's IC System, collection agency, they have been using various phone numbers in order to call, 603-414-1929 is another they use.

IC Systems on behalf of AT&T - they also call from 202-870-5875 & 651-204-1362 & 651-204-1347

They never leave a message but through my research on here I've figured out is the collections company for AT&T

I want to know who they are.

grrr....they just don't stop.
I am making payments directly to AT&T.  next week will be last payment...will the calls continue?
To my cell phone too...isn't that illegal.  I have asked them to stop, told them I was paying AT&T directly.

Thanks for the information.  Has anyone figured out if this is illegal?  I do not owe AT&T any money.  I use Verizon.