If you had sold your shares on April 8th then you would have received the cash in your account 3 working days later.
I think what you mean to say is that you placed an order to sell on April 8th and that order was never executed because there were simply no buyers in the market.
The exchange would have issued warnings of a pending delisting in advance.
The problems facing Debenhams were well understood by the market at the time. The share price had dropped 97% in the last two years.
Debenhams was place into administration on or shortly after April 10th as the shares were delisted. Your only hope now is that the administrators can restructure Debenhams and prevent it from declaring bankruptcy.
This is how the Motley Fool UK site rates Debenhams chances:
Unfortunately, this means that anyone who owned shares probably won’t see any money back.
Sorry to be the bearer of bad news.