The goods do not match the sample. What now?
Not matching means one of three things: outside the approved sample range, off-spec processing, or simply the wrong material. Each has a different remedy, and using the wrong one turns a solvable issue into a standoff.
First: which kind of mismatch is it?
Three kinds. Colour or veining outside the approved sample range. Deviation in thickness, dimension, surface or edge profile. Or the stone or grade is simply not what was ordered. The first is natural variation and can be settled by credit or partial replacement. The second is a processing problem and can be reworked or replaced. The third is a fundamental breach and is a return conversation. Misclassify it and every subsequent step is wrong.
What evidence is actually persuasive?
Four things together: the approved sample, either physical or a photo signed by both sides; photos of the delivered goods side by side with the sample under the same light; a measurement record showing thickness with calipers and dimensions with a tape, photographed; and the inspection record with a date. Without the approved sample you are only asserting it looks different. Without a side-by-side photo, they can say the lighting differs.
What is the first step?
Notify in writing within the shortest time after arrival, rather than complaining by phone first. The writing should state what differs, how much of the shipment is affected, attach photos, propose two options among replacement, credit and return, and set a response deadline. Written first, then a call about tone — reverse the order and you are left with emotion and no record.
Credit, replacement or return?
Judge whether the difference affects use. If it is visual only and structurally fine, a credit is simplest and neither side moves freight again. If it affects layout or leaves you short of quantity, replacement is more reasonable, but settle who pays freight and whether the replacement comes from the same batch. For a fundamental mismatch such as wrong stone or wrong grade, return is the only option and the sooner you raise it the better.
What if they deny it?
Three escalating steps: demand a written response referencing the approved sample and the side-by-side photos; then propose third-party testing or a jointly commissioned inspection, with costs on the party whose position fails; only then withhold the balance or invoke the contract's dispute clause. Withholding payment looks tough, but without a paper trail it can be turned into a counterclaim against you.
How do you prevent a repeat?
Write this dispute into the next specification sheet. Not just colour to be judged against the sample, but no visible difference from the sample under natural light, with slight variation allowed within a batch. Not just thickness, but tolerance and measuring method. Vague terms only produce vague outcomes.