Franke Geyser shame

I recently needed to replace my geyser due to the cylinder rusting and leaking. After the old Franke Geyser was removed, we found that it was still in the warranty period. I contacted Franke to start the claim and they said it was now void as I had removed the geyser.

I went through the warranty booklet and nowhere in the booklet does it say that the geyser has to be installed before you start a warranty claim,

The warranty manager Jason also attempts to use phrases out of the warranty booklet, out of context to try and not validate the claim

Then he send a list of points that they use as Void Guidelines, that they use to try and not process claims.

They offer a void letter to give to your insurance?

Franke also do not make geysers anymore, surely they should admit that they had a problem and rectify it.