You can restart if you had previously linked your account to Facebook. If not, then your banned account's data has been saved to your device and you device ID is banned altogether. You have to download parallel space to start again. Or factory reset your phone which will remove every single thing in your phone by now so do some research and make your decision. If you have connected to Facebook beforehand however, you just uninstall and reinstall and you'll get a different account from the start and you can again link this account to facebook.I barely started to play and ended up banned during that multiplayer section that I didn't know about. How to delete the data and restart? Do I need to link a different account? I have a tablet only since recently.
This thread if full of ways to not get banned and people sharing their experiences, makes sure to read them if you start again.