Sangoma A200 caller hangup not detected

Hi all, have just installed the Sangoma A200 card into a system running FreePBX Distro. The Sango card is used for all incoming calls from BT as we wanted to keep our number, however it can’t be transferred as it has all of the services on, such as Broadband e.t.c.

So as it stands the Sango card is used for all incoming calls, and all outgoing calls are routed via a SIP trunk (different number) via VoipOn.

However, the Sango card is having difficulty detecting when users have hung-up on the line, therefore keeping the line busy and other clients not being able dial in.

I have contacted BT as there is an article out there that recommended BT change the ‘Disconnect Clear Time’ however BT sales (who apparently deal with this) are closed until Monday. Is there any settings that we can change to overcome the issues we’re having? I have used the following articles:

However haven’t had much luck.