Incorrect advise and strange communication

I would like to lodge a complaint regarding the advise given to me by Alpine VW Hillcrest, I have used this dealership previously and service has been outstanding up until today. Background, I contacted the dealership to boom my vehicle in for a service, The service due is for 60000 km which I understand is a major service, With discounts etc - the price given to me was approx R7000. I did enquire before booking the vehicle in if a service plan could be taken out and weigh my options, The cost for the service plan was approx R10000 hence it was not viable to go ahead with the service plan. I booked the vehicle in and later got a call that the transmission oil must be changed, the cost for that was approx R5900, I then told the dealership that the service plan is a better option and they agreed, but then told me that the car has already been logged in and the service plan cannot be taken out. I have a major concern with the back and forth on this, I also believe I was advised wrongfully, I have told them to continue with the major service but to hold on with the transmission oil change. Please can this matter be addressed,