Who called from 2136299076

It hang up as soon as I picked up the phone

This is apparently the fax number for Andiamo Telecom. I have gotten the same call (just had one a few minutes ago) every so often. No idea what it's all about.

this number calls my cellphone then hangs up/ when i call back its busy. Not happy about this. whover they are need to be stopped.

Called my cell which is also my business number.  Asking strange questions which regarding wanting to 'challenge' me.  Gave me the creeps so I hung up.

Uncertain of the nature