If the adjustments just keep coming you have a business problem and no "process" will save you.
You might as always happens attack them for not doing Scrum right, and I'll tell you that's the age-old cry of the agile-folks: you're not doing it right, and nobody ever was.
Fuck scrum, it's not agile, never was and never will be.
Thus, the odds of a team knowing where they are going reduces drastically if they start doing scrum.