do you have a recovery method set up such as email, Facebook, Game Center or Play Games?
if so, I would try:
clear cache on DS
clear cache for app store (different depending if droid or what ios version but instructions can be googled)
reboot the device
this should give you a clean slate that launches into the tutorial.
Support, Accounts, "Lost Account?" and recover your old account.
You will wind up w a level1 account on s11 probably. You can try other peoples' suggestions first, if you wish. That's the best way I know of to at least get DS running again and go from there. If it's the same physical phone you have used before and you have a recovery method handy, that *should* go smoothly.