Gold and purchased upgrades are specific to each platform, and cannot be transferred between platforms. (EG. Steam -> Android, or Apple to Android etc...)
If you are playing on Mobile, your Gold purchases are saved within your specific device and cannot be synced across multiple devices. However, we're always happy to help in situations that allow it (EG. Android -> Android, Apple -> Apple). Email us at [email protected] and we'll see what we can do. Don't forget your App Store receipts and PlayFab ID (Tap on the Menu (three lines at bottom) > tap the '?').