Infant is not considered a passenger

Dec my baby and I were booked on a flight back to CPT. We were delayed by 2 hrs. I received a text message later saying the Mango will give me a voucher for the inconvenience. I have been calling mango for 3 weeks now regarding the voucher. They initially advised me that they issue one voucher per passenger and I would be receiving 2. I repeated this conversation numerous times to them to ensure the information I was receiving was correct. 3 weeks later, I call to follow up on my 2nd voucher. Only today I am told that it won't be issued cause I was travelling with an infant. It is unacceptable to think that because I am travelling with an infant, the infant is not a passenger. Also the fact that commitments were made regarding this voucher, and now they are going back on their word. At the end of the day, it is an inconvenience for any flight to be delayed despite what kind of passenger you are, esp when you have an infant. I purposefully booked for 6pm so my baby could sleep and it would make it all round easier. She did not sleep. Instead we had to push around the airport for 2 hrs in order to placate the baby. The question remains. Is she not a passenger just like me.