Matric Farewell Dress

We bought a R4000 dress and was promised that Bride & Co would ensure that no other person from the same school would be sold the same dress colour and style. My daughter got to the venue and whaLa, the lady walking the red carpet behind her had the exact same dress bought from the exact same Bridal&Co store 4/ 5 months after us. We complaint and was offered a R500 voucher whilst Bride & Co refunded the 2nd purchase in full? Very upset and disgusting behaviour from B&C. The company is not answering my emails and telephone calls. Please help.