With medical & ambulance bills that are being paid off monthly and aren't finished yet, how can you list how much of your payment went to each item? Like the miles?

I have separate payment plans for the medical and ambulance bills, that are still being paid off. The receipts from my payments don't specify which items my payment went to, as they only subtract from the total bill. However, I still have the itemized lists of what the bills actually are. Like lets say the items for the hospital are A, B, C. The bill is 1,000, and I've paid 600 so far. Should I just assume that my payments were split equally between A, B, C when itemizing?

And for the ambulance, you only fill out how many miles it was. So if my ambulance ride was 10 miles and the bill was 1,500 and I paid 700 off so far, am I still supposed to fill out that my ride was 10 miles, despite it not being paid in full? (Probably not?)