I wanna tell you my own experience,

I guess you are not familiar with the process of the site management. In practice all the site members are liable to pay for the common expenses. What I pay depends on the baskan-president of the site or for the more intense sites there is a committee consisting of a couple of the people who live in the site and who have enough free-time to deal with the site issues. For all the expenses the the site management has to show a paper some sort of balance sheet, and generally they hang it to a notice board. So that everyone can see itemised expenses and clarify any other issue. For my own experience, people had to pay monthly fees for the houses even no one lives in there. The defending point is that there is always a fixed cost for any site such as external lighting, gardening, security, consiarge etc,,, ( I want to give you some examples for the monthly 'aidat' that people pay; one f my friend lives in a reasonable apartment flat, and they pay around 40-50 TL for the common lighting costs and elevator's maintenance, and someone else is living in a quite luxury site costing 200TL monthly, and another one is 400 TL monthly) Also in a site consisting 40 flats, one guy owns about 18 flats awaiting for sale; -listen to this-, every month he is paying 200x18!!!

Site management is easy to abuse, this is another point. but if you are not happy with the management you can call all the site owners and ask for a new management etc... Also if the amount is quite high and you beleive that there is an abusive attitute, I recommend you to consult a nearby solicitor (considering the cost-benefit ratio of going to the court to resolve if it worths)

According to your statement, the easiest way is to clarify the documents of the expenses and if the amount being asked is a fair value or not, adn discuss it with other home owners/tenants of the site... Because legally you have right to see what is going on in the accounts..