Short sighted customer service

My wife and I were regular patrons at Bunga Spa. I was given a voucher for my birthday last year ( together with vouchers from other spas) . All my other vouchers had a minimum of 1 year validity (up to 3 years). Unknown to me when I booked and arrived for my treatment the Bunga Spa voucher is only valid for 6 months. I should have checked the voucher earlier but didn't. We had booked treatments for greater than the voucher value but were told that the voucher is now only worth half of its value. They refused to honour the full value of the voucher even if it meant that they would lose a regular customer forever. I find it hard to believe this short sightedness from the owner who refused to bend her "rules". Sad really.