Disappointed in pnp

Am so disappointed in pnp. My partner got a voucher from his niece and the voucher does not have an expiry date. When he went to buy with it today being the 4th of June, he was told it expired yesterday the 3rd of June at midnight. I can't believe they cant let him buy with it when it's only a few hours expired, especially with the lockdown, people need to make use of all means to buy food. now hes lost out on that amount although there was no expiry date on the voucher.