Complaint Review: Nextiva

I had a horrible experience with Nextiva.  First off, their service is horrible.  I would constantly have clients tell me that my phone was crackling.  I finally decided to make the switch from Nextiva and had all of my numbers ported out.  They have been billing me $47.00 for 7 months for a line/number that had already been ported over.  I have been paying two phone companies for one toll free number for 7 months.  I've attempted to cancel this multiple times and they continue to charge me.  On March 26th, I spoke to them and they told me that I would not be charged anymore and that I would receive a refund for the past charges.  I was charged again on 4/24/15.  I spoke to a supervisor today and he told me it was my fault.  Why would you tell me that you're going to give me a refund and not charge me anymore, and then not do it?  Horrible customer service.  They lie to you and then blame it on you.  I will never do business again with Nextiva and I will continue to share my experience with others.