I've run into a problem with this, after managing to pay ok with a UK card in the past.

2 debit cards are declined, and using Paypal with either of them doesn't work either.

Unfortunately I've managed to leave this late, so the SIM may be dead by the time I can contact them or try that saveonroaming site next week.

Can Wind reactivate SIMs which go slightly beyond the expiry date, like UK networks will do?

No, they don't, afaik.
Dial *123# to check if it's still active, or *124*4242#.
In case let me know to see if I can help you from here.

I think I might ask your help with this.

I've phoned up a few times to phone numbers I could find, asked if they speak English, and asked to be transferred to a call centre, as calling 155 is impossible from outside Italy. Not much progress so far.

Even if they can't be persuaded to reactivate, one thing I might like explained is why they sold my contact details and I've received unwanted email trying to sell me an insurance product ..... [edit] and 2 other products