Amazon's bots are absolute garbage and Amazon Seller Support is utterly hopeless. If sellers can't solve a problem on their own then the problem won't get solved.

As for your issue here, this could be down to some conflict between the various unit counts and item counts in the product details - you say the price per square metre should be £7.87 which is about 1/6th of the value it's claiming and there are six items in the pack.

It looks like it thinks the *total* area is 50cm x 55cm (rather than the area per item). You can try adjusting the details in the product page or uploading them again via a flat file (just download the correct template).

However, Amazon takes the information provided by sellers as mere suggestions and will often consider the values plucked by its bots out of (let's be charitable here) thin air to be more relevant than those provided by the person who created the listing, is actually holding the product in their hand and, in many cases, even manufactured it themselves.

If they refuse to accept your submission (the flat file upload results will often say that your values don't match the catalogue and you should change your values to match theirs) then their stated remedy is to contact Seller Support - at which point you might as well write the listing off and create another one, this time supplying all the relevant values yourself and hope the bots don't change them later.