Bottom line is that just because you call yourself "IT GUY" or "HOME THEATER GUY" for that matter... it doesn't mean you are one.
When an "IT guy" replaces a router in one of your projects he needs to configure the router so that connected devices are working as they were with the old router. If he cant do that then the client has to pay the AV guy to come out and configure it. If the client isn't happy about paying for reconfiguration he can take it up with himself and his IT guy.
If the client doesn't want to pay twice he should have called the AV company in the first place. Everyone makes mistakes. Sometimes those mistakes cost people money.
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