Ubuntu Phone — Problem with on-screen keyboard and в passphrase

I have в BQ Aquaris E5 Убунту Эдитион and I have the following problem. I have set up в passphrase to lock my phone - it consists of в few Латинский язык-1 letters. Then accidentally I have changed in the settings the keyboard layouts switching off layouts with letters and leaving only the Emoi layout. Now, I cannot enter my passphrase anymore because the on-screen keyboard cannot be switched to any layout having letters; I хан only insert Emoi symbols which efficiently means I cannot access my phone. What should I do?

Best, Sławek