They may have had the bike for 8 days but how hard are they looking? A small electrical prob is not a big earner so if they start changing expensive bits or talk big money, get the bike back until you have had a think yourself and had some feedback through here.

Blowing fuses is often a shorting wire somewhere and they can be a PIA to find but are usually inexpensive to fix. It usually involves a careful and systematic inspection of the loom and all the connectors. Just 'cos they are dealers it doesn't mean they know things