R400 Voucher not being honored by Hussar Grill

I have a voucher and cannot seem to use it. I booked a table, after confirming the validity of the voucher, at Willowbridge and when we got there I was told its not valid for that specific branch. Strike 1!! Back at work I emailed the H/O. Barry Rheede asked me to fwd the voucher on the 14th of March so that they can assist me. On the 18th of March I followed up and got no response. Strike 2!! On the 3rd of April I emailed again stating that its now been 3 weeks since my first mail. Got no response. Strike 3!! Now someone paid the R400 over to The Hussar Grill and gave it to me as a gift and I cannot use it. Nowhere on the voucher does it give a expired date but also nowhere does it mention at which branch I can actually use it. So what now? They have the R400 and we cannot get feedback on where we can have our meal. Thank you for nothing Hussar Grill.