ABSA insurance passing the buck

ABSA insurance arranged that a Duratherm geyser be installed after the geyser in the insured property burst just over three years ago. Now ABSA insurance are wiping their hands of the issue and say its Duratherm that must replace the geyser. Try contacting Duratherm. They dont answer their phones. So no one takes responsibility and my tenant sits without hot water. I hold ABSA insurance liable as they installed an inferior geyser judging by Hello Peters ratings of Duratherm and now when it comes to the crunch the client must try get Duratherm to honor their guarantee. Shocking service from both parties.