Hi @nain1959 and welcome to our adorable Community 😊 I am sorry this happened to you. The boosters we collect are stored on our device's memory. This means that even if we are offline we can reach them. Unfortunately, it also means that if we reinstall the game or change the device we will lose all the boosters. Therefore we do not recommend collecting a lot of boosters, it's better if you use them while playing. You can read more about safeguarding your boosters on the link below.
Now, I know how inconvenient this is as it happened to me but it's handy to know for future use. Thank you for your understanding. Have a wonderful day 🤗