partner cancelled package, im joining as new customer for deal, how to not be without internet inbetween?

So we cancelled our vm package because what they offered us was way above the new customer package and as i have never been a customer with them im going to get it.

we're in the 30 day cancellation time now and i was wondering when i should buy the new package so that we aren't without internet for ages. we don't mind paying for a bit of overlap but don't know if vm will give the new router for new customer package before the old one has finished?