My error. For some reason when writing my response, the 4th got stuck.
In any case, based on your information, the landlord appears to be in TECHNICAL violation of the 21 day allowance by one day. However, I doubt that a court would grant you relief based solely on that issue..... it would depend largely on the court and their 'feeling' on the day that your case is heard. I recently had a case where a court ruled against the plaintiff when the landlord failed to comply after several MONTHS!! The court accepted landlords statement that she was an 'amateur landlord' and shouldn't be presumed to know the law!!!
(Case is currently under appeal!)
So, if you feel REAL lucky, go ahead and file a small claims action against them for your 'damages' as allowed by the Admin Code. The worst that could happen would be the court deny your request.
BTW, what the hell does ANY of this have to do with "Child Custody, Visitation and Support"???