Welcome to the Community @Anonymous
When you changed your tariff did you discuss with the advisor about upgrading your contract early with a new device? If not then there is probably little you can do.
That said when you go through to upgrades I would discuss this with them as they may offer a good will gesture given the circumstances.
If the first advisor declines. Don't lose hope. Politely thank them and say you will think about it then call up again to a different advisor and try again.
Good luck