I'm in the same boat, and I was also only in the store last week, but didn't use the whole value of my gift card.
I'll be going in-store tomorrow, but I'm not hopeful I'll be able to use it.
Just saw this on BBC News "The firm said it would not be accepting gift vouchers or issuing any more." Here: http://www.bbc.co.uk/news/business-21021073
I'm really fuming about this and as far as I am concerned both HMV and their administrators are cheating, lying and thieving bastards.
I don't know how they are allowed to get away with this, they have £20 of my money (and I'm sure others are in the same boat) and now I am going to get nothing, through no fault of my own, exactly how is that any different to stealing?
Why are they allowed to do this, why should they be allowed to simply dismiss their responsibility to their customers (honouring gift vouchers that might have only been purchased mere weeks before the collapse) because they have gone into administration.
I know to some £20 isn't much but to me its an awful lot as I'm unemployed and what little I have goes on essentials, that voucher would have been a nice little treat for myself if it wasn't for thieving gits like HMV.