DRC is telling me I need to purchase the software but i have already purchased (mobile only).
Try to restore purchase - Ensure that you have your device configured with the same account you have made the purchase with. Open DRC, open menu, choose Store, tap Restore Purchases.
Restore purchases doesn’t do nothing - Sometimes, in some devices, Restore Purchases is not working. If this happens, choose to purchase the same item (you won’t be charged again).
If any of the above don’t work - A way to solve this problem might be to log out of the app store in settings, re-log, reboot DRC and try to restore purchase again.