Double Billing by Comcast - Need Corrected

I hope someone from Comcast Billing can help me. 

I have the Business Starter Internet plan from Comcast. I switched from the Comcast-owned modem to my own modem back in September 2015.

Ever since then, I am being double-billed. On my bill, I see two separate entries for Starter Internet Package each at $69.95. But I am being billed twice in the same bill. 

Can someone please help me? I have called Comcast. They acknowledge that it is a problem. They promise someone will call me back after correcting it. It has been 3 days since the Comcast rep said they would call back.

I also have a Comcast Ticket # that the agent gave me.

Any help is appreciated.