Problems with undermount sink fitted to a quartz worktop

[stuey2407]

I fitted a new kitchen at the beginning of the year following an extension. We went all in a selected a company to fit a quartz worktop. The sink is a Franke 1.5 bowl under mount sink, 700mm wide.

The worktop was templated and subsequently fitted. When it came to the sink the fitters sealed with silicone and used blocks of quartz to create brackets which were glued in place with what looks like a two part epoxy.

6 months after fitting we notice water in the cupboard underneath. On closer inspection the sink had dropped on the front edge by about 4mm breaking the silicone seal. I had also noticed that the block on the left at the front wasn't in contact with the sink so had room to fall onto the top of the block, i.e. it provided no support to the sink. On the right hand side there was another block on the front but there is only room for it to be epoxied to the sink lip. The sink is so close to the right that the edge meets the side of the unit. There are no block or supports on the front end. Again it is touching the cross bar of the cabinet which has been cut back. So no room for any brackets.

The fitter returned today to fix the problem and just stuck the sink back up with some more silicone. I wasn't in but apparently, and in their words, it is much better than the last silicone they used so won't be a problem again. I have no reason to believe that in 6 or 12 months time it won't fail again. To top it all off the failure of the sink and the water leakage has also caused the front edge of the carcass to start to lift slightly.

It feels like the sink should have been positioned further back and further to the left to allow adequate space around for fitting proper clips that are properly secured to the underside of the worktop. I am not sure what is the next course of action to take. Any advice would be greatly received.

I have attached some photos which should help to explain the issue.