I've been using 3CX for about 2 months and my system seemed stable and clear, but over the past couple of weeks my call quality has been terrible. Local extension to extension calls are still crystal clear but incoming and outgoing calls are horrible. I've been taking numbers for inbound callers and calling them back on my mobile, not the way my company needs to do business. It's not a bandwidth issue because there is very little running over my network, and it doesn't seem to be related to a specific time. Flowroute is my SIP provider and they have been working on the issue for several days without a resolution. I want to be able to install, configure and resell 3CX phone systems but if I can't make it work for myself I could never have the confidence to resell the product. Any suggestions would be greatly appreciated.