Century Link Broadbandnetworx Price does not reflect agreed upon proposal. Monroe, Louisiana

My business is located in a rural area.  In these rural areas, apparently, Centurylink contracts to local sales groups to do business level sales of their telephone and internet services.  I was approached last year by a representative from Broadbandnetworx, one of these authorized sales groups, as my contract was out of date and needed renewing.  She came up with a  competitive proposal for my account including internet, telephone, and long distance.  The price quoted was $239.36, I still have the proposal in an excel spreadsheet.

So, I agreed to the terms and signed the agreement.  A couple months went by and I noticed that my bill was not reflecting the agreed upon price.  I am paying about $320-$350 per month.  The representative at Broadbandnetworx has stopped answering or returning my calls.  I do have an account rep at Centurylink that has been working on this for me.  He is very polite, but has made absolutely no headway in correcting the charges.

I would like Centurylink to bill me the correct price going forward and credit me for the over-billed amount, or I would like to terminate my contract early so that I can find a more competitive communications provider. I do not think that I am being unreasonable.  Any suggestions or help in this matter would be much appreciated.