I got a good deal on the lens with one small issue. The lens and case are in mint condition but the owner couldn't find the shoulder strap for the case. I can use the strap from my RF 100-500 for now but I want to replace it. I'd prefer to have the OEM strap but don't want to buy a replacement case for it. Has anyone had luck finding these or can recommend a good aftermarket shoulder strap for the case?