Struggle to get feedback for service authority.

Reported to Global Nissan Gezina on 13/10/2015 for service of Hardbody NP300 2.5 TDi LWB P/U and get told that service plan has expired. After looking at the service plan in our possession reads as follows: Period Months Covered: 84. Cover From KM: 120000. After been sent from one person to another for two days and been told they will adjust the policy and get back to us. The policy states 84 months what do they need to adjust? The policy was signed on the 27/09/2011 when the vehicle was bought. The vehicle is still standing at Global Nissan Gezina! The vehicle has been serviced under Avis for the last 3 years. The vehicle's KM is +-31 108 and is due for its 60 000 km or yearly service. Why cant authority be given for the service?