Bad service

I would like to make a formal complaint, I booked with Agoda for a trip to Durban at the Durban spa for the 30th of April up to the 2nd of May so the booking was done incorrectly by agoda I have made a booking for 6 guests which was 3 adult and 3 kids 2 × 10 year old and 13 year old and Agoda sent me confirmation which said 4 adults and 0 children.They sent me an email to say that they were gonna attend to my matter without any extra charge then the following day they sent another email saying that said it's either I cancel or rebook of which I did cancel now they're telling me that the refund is gonna take 15 working days of which is gonna be a problem we need to make a booking and confirm it as in last month.please refund Asap.