Hi, I'm having similar issues except I got the message - paraphrasing - that I am only allowed to purchase the 1yearmembership once.
Could I use the $15 donation as a workaround to using the membership link? The add to cart link on the purchase $15 dono url will actually bring up the cart at the top left.
Also oddly if i then go to https://gamrs.co/index.php?/store/cart/ it shows as empty but if i go to https://gamrs.co/index.php?/checkout/3199/ it shows the $15dono item..refreshing both pages in the same order shows the same thing..
*edit*
nvm to the workaround request making another acct