@Sunnybest Use a PC and go to https://wallet.vite.net/ (use Desktop mode if using mobile browser), import your account there using your seed and you can unstake via Quota Management menu. You will be able to unstake after 3 days of staking.
Due to additional security requirements added recently, some phones will get this error. Unfortunately, you cannot do anything for this issue right now. Please wait and we'll update if something changes.