called me like 5 times in 1 day! random numbers keep coming in recently it's annoying...

You can sue any 3rd party debt collector who calls you. It is an FDCPA violation.
Let them call numerous times. Gather the info. File a lawsuit under the FDCPA.
Each violation can result in $1k to $1.5K and every state has a mirror law of the Federal FDCPA
So, that's double for each violation.
They will stop calling when hit with an FDCPA violation fine or go bankrupt.

CALLING AND NOT SAYING A WORD ... Keeping you on the line for a few minutes than hanging up

Back at it....

Just keep calling, no sound and hang up.