Recently I have busied out a T1 in a trunk group of 4 T1s. We are now getting complaints from customers receiving a network announcement saying "your call has not been completed, please try your call again." I am confused as I assumed that the network would see these trunks as being busy and not try to send calls down those trunks. If I put it back in service we have no complaints. Is there something that I am missing or need to assign in my trunk group for those lines not to be hit? Even when I remove those trunks from the trunk group they still receive that message. The network says the only thing they can do is to remove that T1 from service, but we want to be able to add that T1 in the case of an emergency. Any suggestions or ideas where to start would be helpful. Thank you.