Mahindra South Africa Tow-bar fitted by BTM

I am the proud owner of a Mahindra XUV 500, 2015 model. When this vehicle was purchased, at Mahindra Menlyn, it was sold with all additional extra's such as the nudge bar, side rails and tow-bar, to actually get rid of the old stock, and also included was R5 000 diesel voucher, form Mahindra SA. During the five years I have been so impressed with the vehicle and the friendly service I received from the Centurion dealership I even bought a second Mahindra, the KUV 100, two years later. I never used to tow anything with the Mahindra XUV, until recently. The trailer's lights didn't work and realised that the fault was not the trailer but the trailer plug on my XUV. I took it to the dealership and was told that the trailer plug was never installed according to procedure/fitment instructions. I had to pay R2 334.43 for a new trailer plug and harness. I was also told that the way it was installed could have damaged all the electronics on the vehicle. I took this up with customer service at Mahindra SA and reported that the trailer plug and tow-bar was fitted by BTM and they incorrectly fitted the trailer plug. I also requested some form of refund. If it was correctly fitted, a mere fuse would have had to be replaced at around R30.00. But this was not R30.00 but R2 334.43 of which Mahindra SA added to the original sale in 2015.. Problem is, that BTM is an accredited fitment Centre for Mahindra SA and that Mahindra SA must unfortunately carry the risk if fitment centres such as BTM makes mistakes like this. However I am now told by Desire Smith, Sales Manager of Pre-Owned Vehicles at Mahindra Menlyn that Mahindra SA cannot compensate me for items fitted five years ago. The principle remain, if this item was fitted correctly I would not have to pay for incompetence which was supposed to be covered for, if proper fitment centres were chosen to do work for a company such as Mahindra SA. Mahindra SA is still accountable.