From the management company for the block of flats I live in:
I am quite happy to [do a load of outstanding maintenance work] except looking at the accounts [...] GBP 8,125.05p is outstanding due to non-payment of some residents and owners. [...] I [...] would ask that you encourage debtors to pay their dues, so that I can continue with the [outstanding work].
Frankly, I think that if the maintenance company has been sufficiently asleep to allow 8K of unpaid service charge to mount up (on only 10 flats!) that's their problem. I see a snotty letter in their future...