* -ed: This is the most common way to form the past participle of verbs, and it can be used to indicate something that hasn't been adjusted, e.g., "unadjusted data".
* -ing: This can be used to indicate something that is in the process of not being adjusted, e.g., "unadjusting the figures".
* -able: This suffix indicates something that can be adjusted, e.g., "adjustable rate mortgage". You could use this negatively, e.g., "non-adjustable".
Ultimately, the best suffix to use depends on the specific meaning you want to convey.