Now that you have switched device types the reason you will experience difficulty is that we use the Mobile App Industry’s Best Practices to process our subscriptions and payments. This means that we sync your Apple ID or Google Play Store ID to the device used to subscribe. This is designed to prevent multiple people from sharing a single subscription.
For the app to work as intended I would recommend cancelling your subscription on your old phone.
For Apple subscriptions please follow this guide: https://support.apple.com/en-gb/HT202039
For Google Play subscriptions please follow this guide: https://support.google.com/googleplay/answer/7018481?co=GENIE.Platform%3DAndroid&hl=en
You will then need to send a screenshot of your cancellation to our support team using this form here so they can issue you a code for any lost time on your current subscription.
Do not subscribe until you have the code or you will be charged again.