Re: Router/Internet nightmare!
so the DHCP , you mean on the WAN or LAN. If they took your static IP address and replaced it with dynamic address, well that is why your vpn will not work.
what flavor of broadband ? sounds like DSL
If it is dsl there should be a "keep alive" or keep connected setting in the router. It should be on the page where you configure PPOE. Sounds like it might be set for 15 minutes or so
try doing a complete reset of the router, write down all the settings, some routers the settings can be saved to a pc, then imported back into the router.
by the way what madel router and manufacturer. ?