I've already checked on this before and building codes will allow vinyl right on top of OSB but it isn't a good practice just for the problem you describe. Check with your local inspection department as to exactly which code you are under and if they have any local variations. Tyvek would have helped but water will eventually work through it also. Tyvek may not help keep it out of the attic though. House siding is not waterproof/watertight. With sustained rains, etc. and being wind driven will allow water and moisture to soak into and through siding. It then takes a while for everything to dry out. Rain and moisture can be driven in through your attic vents also which is hard to stop.
Tyvek would have helped with wind which may help your house stay warmer.
I do have some concerns about the insulation drying out and with the mold and mildew forming before it does dry out. I also suggest you file an insurance claim as the contrators insurance company may say it is storm related and not a warranty issue and then that would put it on your insurance to pay for the drying out and any repairs. Search down below, we just talked about this with someone else. Fix it now or once mold and mildew get in, you may be looking for a new house. Good luck.