Phon's Thai

Last night I went to Phon’s Thai in Minyama. I would count myself as a regular including taking my in-laws (from WA) there last year for dinner, they knew how much we liked the place and for Christmas they got us a $100 voucher. We had used $45 since Christmas. I went to use the rest last night (as vouchers are usually valid for 12 months), I was informed that it was only a 3 month voucher and they would not redeem the remaining $55. When I asked for management and explained that I am a regular customer and did not realize the voucher was out of date, his response in a nutshell was basically “that was my issue and the money is now there's”… The way management spoke to me was extremely rude and should never be a way you speak to your customers. I will NEVER be back and would never recommend this place to ANYONE!