Call forwarding and charges

Hi all,

AM trying to do a call forward with code below: Like if caller with cell phone number 123 calls the number(124) the SIP provider gave me, the call is then forwarded to callee with cell phone number 125.
The call forwarding is working fine but the problem is that when caller is talking to callee, caller still sees the SIP number 124. With this it seems the SIP provider is also charging me for this call?
Is it possible that when caller and callee is talking that the Asterisk does not mediate the call?

$agi->exec(‘Dial’,“SIP/provider/external_number(125),35”);

You might be able to take Asterisk out of both signalling and media paths, by using Transfer(), but, expect the service provide to charge you as though it were still in the path. That’s the normal, commercial, approach to forwarding public network calls.

Noted and thanks @david551