Bad Customer Service

My NP200 recently developed electrical problems and started misfiring.I took it into the service centre it was taken for a battery test - which passed. Nissan Gateway had the vehicle for the whole day and at 15:00 told me that they could not find the problem and the vehicle had to be re-booked.Due to work commitments it was impossible.The Foreman stated that he would make a plan and revert to me.10 Minutes later he reverted and said it was the battery.The following week I took the vehicle back as requested.Again it was said that the battery was the problem.They replaced the battery at R1800.00 which is a rip-off but I was in for R770.00 for the diagnostic test anyway.The following week the same problem returned.When starting, you can now clearly smell plastic burning.I was told to phone back and see when the courtesy vehicle has been returned, which is not service.A week later and nothing.Despite having left messages, no body returns the call.In the interim, the starter motor and new battery are taking strain. Will Nissan replace same at no cost due to their lack of interest for not making a plan to satisfy the customer?I will not be returning to this brand in future