I think the 72 hours thing is a load of codswallop. Whoever told you that must be one of the newbie support staff and very confused.
If 72 hours means anything, it is likely to be the maximum time a new installation takes to settle down, (and that means down not up), barring a fault existing.
I would try a single restart of the modem some time between 10am and 4pm and see what happens. To do that, pull out the power cable but leave the VDSL one in, then wait a couple of minutes before powering up again.
Edit: PS - did you disconnect the modem from the phone socket as well in the thunderstorm? Lightning can fry it and your router and anything hard-wired to your router through that even when things are powered down.
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Edited by RobertoS (Sun 13-Apr-14 13:21:59)