Adidas voucher promised but not delivered

After struggling for two months with virgin active to send me my Adidas voucher, nothing has happened and they do not honour their agreement with me. I visited the gym for more than 24times, as stipulated in the promotion , they confirmed that it would be sent and that I qualify for it...still no voucher. These vouchers are only valid until end February 2016. I do not know what else to do. My husband received his voucher.