Electronic Steering lock Fault

My 2009 Mercedes Benz c200 AMG broke down without any warning. After being picked up by a flat bed truck and taken to Mercedes Benz Umhlanga , I was advised that the Electronic Steering lock was the cause.<br> This was subsequently repaired and my car was handed back to me in 2 weeks. AS my vehicle is no longer on motor plan , I was left with a bill of R8000. Upon investigation , I found that this was a common 'fault' across the W204 range , and a fault that was occurred after motorplan had lapsed. I subsequently requested for some goodwill or discount on the amount, from Merc SA . As this is a FAULT on the vehicle , Merc Sa should bare some of the cost associated with the repair. However ,This was denied for reason not communicated to me. I logged this Complaint with Merc SA via there website on the 9-03-15. apart from the automatic email advising that I will get a response , I have yet to here from a representative from Merc.