Blocking a specific outgoing number

[nMitel]

Solved!

 I had to block the number on access code #6, not 9 because that extension did not use to dial 9 to get an outside line, seems like it resides within #6 access code.

Thank you very much for the help.

[acejavelin]

Solved!

 I had to block the number on access code #6, not 9 because that extension did not use to dial 9 to get an outside line, seems like it resides within #6 access code.

Thank you very much for the help.

Ahh... the plot thickens and is solved.

Actually, this isn't that usual... The SX200 has a feature called "Direct to ARS" where you set the code that is essentially "dialed for the user" when they go off-hook. I would guess if you dig into it, you would find this code is set to #6 and this users COS has Direct to ARS enabled. In that case, it makes perfect sense.