Promises delivery and then doesn't

On 25 th September 2015 I entered into a business arrangement where passport 2000 promised delivery of 3 certificates (2 Marriage and 1 birth certificate) The invoice was paid in full at that time R6327.00. ( R1850 per certificate +14% VAT) On 28 th Oct I was informed that 1 certificate had been received and was ready for collection but that the other two were still outstanding. They blamed the fact that someone else at some stage had app**** for the same certificates and therefore they can't complete their assignment. After more than 8 emails I still do not have the outstanding 2 certificates or the refund of my money (R4218.00)