The ball is in the authority's court and what happens depends upon the grounds of your witness statement.
If, as seems likely, these were 'made reps but did not receive a NOR' then the authority must refer the matter to the adjudicator for their directions. In all probability, they would require you to produce a copy of your reps. It's also likely that the authority would provide you with a copy of their NOR.
In this process you cannot prove a negative, neither should inferences be drawn from your change of address. If you can show you made reps in time and a NOR was issued then the adjudicator should accept that this was not received.
