This could be a great opportunity to resubscribe directly with The 4 Blades! You can do so by following the instructions here: http://lp.the4blades.com/current-subscribers/
If you would like to continue to be billed directly by Apple, you can follow the instructions to update your payment details here: https://support.apple.com/en-au/HT201266
After updating your payment details with Apple, you are free to subscribe again through your app.
Please note, however, that due to privacy restrictions we are not able to see the purchases you make via the app and therefore cannot add them to your web account without you sending us your purchase receipt.