Vets warn against Catmor

Add another death to their death count. Two days ago my male neutered cat was not eating, drinking or standing up. Took him to the vet - crystals in his bladder. The vet asked me if I'm feeding him Catmor or Epol, yes I feed him Catmor. Vet removed the fluids and crystals and let him stay overnight. Phantom didn't make it, my heart is in pieces.