You can make it much easier for the customer. A single link.
Find you Seller Profile page on Amazon. It's a page that lists your company feedback, policies, etc. On that page you will see "Have a question for X?" and an Ask a Question Button. Click that button. You may be asked to sign in first. Now, when you get to that page copy the URL in the address bar. Then take that link to a site like Bit.ly. There you can make a super short link to the super long link that is your contact page. It will be something like amzn.to/2DFe4. If you like that, then just put that link address on your inserts. If you don't like that you can also get a bit link that would look something like bit.ly/yourcompanynamehere. Use whichever you like. The link is permanent so it will always work so long as Amazon doesn't mess with that contact page and change the address.