Urgent! HangupCause

Dear collegues!
We urgently need your help!
We have SIP provider (out_trunk) which give BUSY or DECLINE after ringing instead of NO CIRCUIT AVAIL (call -> ringing - busy/decline instead of call -> no circuit avail).
We wrote trouble ticket to providers support but they say what cant fix it at this time.

How we can correctly change hangupcause to no circuit avail?

Thank you so much.

Hangup(34) where 34 is the cause code.

To see other codes, voip-info.org/wiki/index.php … angupcause