Had the same happen to me a couple of years ago.
Customer was sold Polished Porcelain.........black/white chequer pattern she wanted.
Anyway.....Topps sold her the Porcelain sealer. So I laid them. Sealed them (Two thin coats)
And she wanted black grout.
Stained all the white tiles...........and it would not come out.
She was going daft at Topps manager...(not blaming me at all) because its wot they had recommended. It went on for months. Talk of Topps paying ME to rip up and do again.
Last I heard they had moved house instead
