I am not sure if AIBU or not. Feel free to tell me I am (but gently!).
I live in a modern block of flats. We have a factor. They arrange all communal repairs etc. Shortly after I moved in 5 years ago they arranged a repair to a particular part of the building which my flat has no responsibility for (it is clearly stated on the deeds that responsibility for that part of the building lies with those who benefit from it's amenity - think communal garage block, only paid for by those who have a garage).
As I had recently purchased my flat and had the deeds explained to me by my solicitor I was very aware of this and questioned it with the factor.
Initially they replied that they had always divided bills that way (ie all flats paid for all areas) upon further prompting they consulted their in house solicitors and the bill was recalculated (my share of the repair was several hundred pounds).
Ever since then I monitor my bills and question items I am not sure about - the most recent bill contains a charge for repair to the hot water system. The building does not have communal hot water. Therefore I have questioned it.
I am doubting whether this is reasonable behaviour as one of my friends has criticised me for doing this saying that it is controlling behaviour. I simply don't want to pay for work that is not my responsibility and the fators past behaviour suggests that they don't always attribute costs appropriately.