Am I missing something here?

I'm going to apologies in advance guys as I have tried to give as much info as possible here...

BACKGROUND
The HR department of my work place have received an Attachment of Earnings Order from the London Collection and Compliance Centre for £800.

I had no idea what this was in relation to, so quickly called the LCCC for more information. I was told the £800 was in connection to a vehicle offence in July 2016 for a car they believed was mine.
Once the details of the car was told to me I explained that I never owned the vehicle but, in fact only insured the vehicle under my policy on behalf of my brother-in-law who was also on the policy and the registered keeper.

The LCCC explained that I was pursued for the fine because I failed to notify them in September (via post) last year who was driving the vehicle at the time of the offence so the case was brought to Court in my absence – hence the Attachment of Earnings Order.
I went on to say that I had not received any correspondence from anyone regarding this and asked what address had been used, of course the address was an old address that I had left a little under a year ago. (this was confirmed by them stating that they had indeed received returned mail from the new tenant)
I asked why I was the individual to pursue given that I was never the registered keeper, the vehicle was not insured by me at the time of the offence and furthermore in May 2016 a whole two months before the offence, the car had been sold on again by my Brother-in-law – which all would have been logged with the DVLA. I was told to speak directly to Bromley Magistrates Court.

I explained all of the above over the phone to the representative at Bromley Magistrates Court who too seemed a little bemused as to why I was even being pursued in this matter. I was asked to fill out a Statutory Declaration Order which is supposedly meant to close the open case so a new case can be opened where I would need to attend Court on the 23 March to state the facts and prove that I never lived at the address at the time when correspondence for the offence was sent.

I was ok with all this until I was informed yesterday that the Court date has been pushed back until the 20th of April and that the Attachment of Earnings order will still be in place and, given how much I earn, the full £800 will be deducted from my next salary.

THE PROBLEM
To me, it appears there are flaws with how information has been collated in this instance but, my main issue now is, when the Court date was originally the 23rd March, there would have been enough time for me to satisfy to the magistrates that I had absolutely no connection to the vehicle at the time of the offence – and then notify my HR team to cancel the Attachment of Earnings Order before my next salary is paid for the 28th.

With the new date being set, I am liable to loose £800 in one hit plus not be able to claim this back for nearly another month and then wait even longer for the claim to be processed and dispersed back to me.
This feels like I am being penalised for inaccuracies of the data collection in this case and, whatever happened to being innocent until proven guilty?