M14 is not there

It should be under Storage-Items tab. When I got it, I joined a server and a window popped up advertising it, at the bottom of that window was a "Shortcut" green button that I clicked. It then took me to my Storage-Items and there was a box with the Red M14 in it with a "Use" button on the box that I clicked to confirm the deduction of 1ZP from my account. After clicking the green button on that window, the M14 was then in my weapons storage.

Clicking the "Shortcut" green button on that advertisement window may be a necessary step to make the M14 coupon appear in your Storage-Items section, I don't know for sure.

I've also heard that you must be the rank Staff Sergeant to redeem the M14 coupon, that's rank with three arrows and a dark space under it. I thought you only had to be Sergeant 1(level 6) that's just three arrows, I think that's the rank you have to be to buy ZP.

Here's a guide about it: http://forum.z8games.com/showthread.php?t=256735