Advice on people ‘scamming us’ on item we sell - e-commerce

Hi I’ll keep this short and to the point , we sell a particular product which is hard to find and source especially in our country,These are absolutely 100% been quality checked and there is nothing wrong with them. However this is sort of like a one use item that you may use once every 2 years. Basically it’s a special bar that checks the alignment of centres on machines such as lathes .Lately we have had a bunch of returns , you can clearly see it’s been used before , and each excuse we get is different.Yes we know this is the cost of doing business , however we really are starting to feel abused and taken advantage of , we know exactly what’s going on, people know what they can get away with when it comes to returns these days.We sell heaps of these and most people do the right thing, but it’s our most highly returned item due to the nature of its use.Can I get any advice on how we can handle this type of thing , we don’t want to pull the product from sale and we also just don’t wanna bend over backwards once people have finished their ‘free loan’ of the item,Thanks see hubwealthy.com/wealthy