Luckily for you, this was a CB Legal issued claim, which we know will be discontinued if defended. If they'd been using a different bulk litigator, the outcome may have been different if you failed to respond to deadlines in time.
When you say that you called the court and they said it had been "withdrawn". Are you sure that is the words they used? Maybe they said "discontinued"?
If it was discontinued and you never received a copy of the N279 Notice of Discontinuation, then you can claim costs against them for unreasonable behaviour by failing to notice you of the discontinuation.
So, If it has been "discontinued", as I suspect, rather than "withdrawn", then yes, this is the end of the process and you have won.
If you wan to claim costs, you can claim up to £19/hour spent preparing for the case and other expenses. It may require a hearing but that would just add to the costs the claimant would have to pay and if you had to attend, you'd also get up to £95 for attendance and travelling/parking costs.