Who called from 5634889925

A number of calls was received by my cell phone at 1:30 am. when calling the number back the response is: "Not in service".

This phone call spooked me, called my business phone that I roll to my cell phone and just complete silence for about 15 seconds that a creepy mans voice said "Can I leave a message for the manager" I told him that we were closed and had to call back tomorrow and then had complete silence again until I hung up. I called back and I am told that the number is Not In Service. VERY STRANGE?

they called me at 2:38 am on tuesday morning. i missed the call, though,and they didnt leave a voicemail