Zenia Wellness Spa unprofessional service

I had a terrible service from Zenia Wellness Spa at Radisson Hotel & Convention Centre, Johannesburg, O.R. Tambo Airport from the Spa manager called Herricah. I bought x25 vouchers valued a R1000.00 each for my clients. I discovered that my vouchers were actually mixed with one of another client, I sent an email to make her aware and she said she'll resolve it but never did. I've been following up with her via email and calls but I get ignored all the time. What was meant to be a good working relationship has turned out to be very sour and I will not be taking my clients there again.