Is it Possible to Hack a Fiber Ont to Turn on Call Forwarding?

[PhoneGuyMark]

We had someone call-forward one of our lines and then make over 450 hours of calls during the next 3 hours.

The phone company says it was done through our phone/voicemail system, we say the dial-out option was already turned off on the phone system.

Is it possible to remotely hack a fiber ont to turn on call forwarding on one of the lines?

[Edg1]

Nothing is impossible but it is very unlikely. Even if call forwarding is activated the outgoing calls that are being  made from the other phone, not yours. For example, if I call forward my house phone to my cell phone, if someone calls my house it will ring on the cell. If I call them back with my cell I'm using my cellular plan not my house plan.

[PhoneGuyMark]

Thanks for the reply. 

The situation is that someone seized one of our phone lines and turned on call forwarding to a number outside of the USA. They then called our number and were connected to the forwarding destination outside the US, therefore giving us the international charges.

Frontier has unlimited call forwarding on our lines so these bad people routed 1667 calls over our single phone line to Burundi and Qatar before Frontier noticed.

We want to know if the forwarding could have been done by hacking into the ONT to turn on the forwarding?

[gs0b · Accepted solution]

The ONT doesn't get involved in forwarding.  It's all done in the VoIP switch inside the Verizon network.

It's more likely someone got physical access to the analog phone line and entered the forwarding codes.