Waterkey Screw - Windcraft Cornet

I'd be loathe to use this company again, for three reasons. (1) WRONG ITEM. I purchased four cornet waterkey screws online after providing a photo and dimensions (M2, 11mm long). The screws they sent didn't fit and they say it's because I gave them the wrong dimensions. However, I think they may have measured their screws incorrectly as the outer thread diameter for the screws they sent looks more like M1.6-M1.8 against my ruler (I tried two different rulers, and don't usually have problems with measurements) - see photo. There are no dimensions given on their website. I asked how they'd measured the screws, e.g. using a micrometer, and they didn't reply. I was initially wary about buying online, but then did so as they'd sounded confident about the sizing. I should have stuck with my original instinct. (2) POSTAGE. They said they'd happily refund the product, but not the postage. However, based on the above, I asked if they would consider refunding at least their outward postage as a goodwill gesture if I cover the return postage. (After all, I still think they've sent the wrong size, they haven't provided any evidence to the contrary, and it was they who chose the outward postage method and package size, both of which seemed rather over-the-top for four tiny screws.) They said no. Given that two lots of postage cost about the same as the screws themselves, and there'd be the effort of repackaging and reposting, I'm now writing this off as a lesson learnt. (3) COMMUNICATIONS. Their initial online contact form failed to include the photos I attached, so I had to send them separately. Worse, their e-mail replies since have taken such a long time, usually 3-5 days for a response and, even then, mostly only after I've chased them up. This has been very wearing and made it difficult to sort anything out. Therefore, at this point, rather than chase yet again, I've decided it's time simply to leave some reviews and move on. In summary, despite the staff sounding friendly and helpful, it has, in reality, been a far from easy or positive experience, and I am dissatisfied with the outcome.

The supplier responded:Dear customer, I can only apologise, I simply have not been able to give your order the attention it deserves and while I am working with more accurate instruments than your ruler, I've not been clear in what I have used and what further information I would have needed from you. I can't supply a screw to your specification, the Windcraft was my best guess, but obviously has not worked. I've issued a full refund for the screws to compensate you for your time wasted. With my sincere apologies, Matt Sanders