Nursery advice

I sent an email at the beginning of August 2024 with my 15 hours government funding code and got a reply from the manager saying she would send it to the finance department. Fast forward to November and I checked my statements and there’s no confirmation of the hours being deducted so I raised it with management and fast forward to December and still no sign of whether they have been applying it or not. I have been overloaded with work and life in general that I didn’t query it when I first sent the code as I presumed the manager would have sent it but I do 3.5 days a week and am being billed £976 per month or £906 on shorter months. I would imagine they owe me some money / backdate it to when I originally sent the code, I haven’t paid Decembers invoice as I think it’s out of order it’s took them over a month and still no response since me first questioning this and now I’ve received a bill of £1812 for December and januarys invoice 🤣 I’ve emailed 3 times and questioned about 6 in the actual nursery. What can I do?