All calls goes to 1 extension

Dear helpers,

I am newly join a company and we are facing a problem. last august our people press 8 on the IP phone and follow by the numbers. When they press 8, all the calls goes to 1 extension which is ‘0000’ and the problem is this extension number is un-assign number in FreePBX. Currently we need to know which staff press 8 and the call goes to ‘0000’.

Hope all helpers(pro) can help me on this matter.

our asterisk version is Asterisk FreePBX

Please help