Important: Please always log into your account the same way you created it.
1. Please try the "Restore Purchase" button on the pricing page.
2. If "Restore Purchase" doesn't work, please check if you have logged into the Apple ID with which you bought the membership. Because Restore Purchase won't work if the Apple ID you're in did not buy the in-app purchase item.
Try logging out in LingoDeer and back in.