Trouble with call forwarding iPhone 6

[Mel_a2]

We've been having trouble forwarding calls from our iPhone 6.  After business hours, calls from our office are forwarded to our cell phones.  After a certain hour we will forward to an answering service.  This has always worked just fine in the past.  In the last month or so we've been having problems.  When we forward to the answering service, any calls that are made to the office will receive a message that says "all circuits are busy."  However, when you call the cell phone directly, the call is forwarded to the answering service as it should be.  Initially it was only happening with one cell phone, now it's happening with two. Both are iPhone 6 running iOS 9.0.1.  I spent two hours in a Verizon location trying to resolve it to no avail.  They actually ended up assuming it was a flaw with the initial phone that was exhibiting the problem and having a replacement phone sent, but this didn't fix the issue.  Any help would be appreciated!

[vzw_customer_support]

Mel_a2 Having calls forwarded is crucial. You have come to the right place. We want to make sure we get this resolved for you. I have sent you a private message so that we can move forward in getting this fixed. I look forward to hearing from you.
RosanneM_VZW
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