BMW Polokwane Negligence

Sent my car for service during December, where it was assessed was quoted for R32 000.00 offwhich i paid deposit of R28000. to my surprise the car was not released up to now. They said they observing additional issues some additional issues. They kept saying that story from december until April. I then decided on the surprise visit and observed the car. I found it visibly wet on the boot and was surprise that they didn't even try to dry it up because it was visible getting rusty. I became worried and contacted BMW South Africa. that is when they were forced to respond and gave me a quote of whatever is the new issues. To my surprise it was all pointing at water damage. The car never had water damage when it left my yard. There was heavy rain in december after i sent the car for service. Their new quotation is at around R97 000.00, i asked them since we both know the damage happen in their backyard, will they be willing to meet me somewhere in paying that amount or they expect me to foot all of it. They have been ignoring me since.