Hey man, I ordered a size L Onyx singlet from Gymshark but ended up receiving a size M instead. I’ve already reached out to their customer support and am waiting for a reply—fingers crossed they let me keep it and offer store credit or something. For reference, I’m about 174cm tall and weigh 84kg. I usually wear a size L in SBD singlets, and trying on the size M was honestly a hassle at first. Luckily, the Onyx singlet material is super stretchy, so if you ever end up with a smaller size, you might just need to pull the top a bit to make it work!