What happens if the court's mistake has a consequence for a case?

[BabyDriver]

Any one have any idea?
This involves another case but is an additional broader issue.
If the court originally denies they have made a mistake (despite repeated appeals) forcing you into acknowledging service for a civil claim that was not served and consequently forcing you into a hurried defence, what should happen, what recourse do you have? They have now admitted their mistake.

[des8]

I would be writing an official complaint to the court requesting extra time to investigate and make an unrushed defence (and withdraw hurried defence already filed).
Their error has put you to a disadvantage and makes a mockery of the overriding objectives as per CPR 1 to deal justly and ensure parties are on an equal footing.
Refer to tanir v tanir [2015] Ewhc 3363 (QB) where a default judgement was set aside as irregular because of a court failure to serve papers.
Admittedly your claim was served, but it was late and did disadvantage you