Can I ask you to clarify something? From the tone of your post I am guessing that you have had very little to do with this management company.
1) Do you own a house rather than an apartment?
2) Have you had any normal or regular invoices from the management company?
3) Have you been attended, or been invited to any AGMs for this company?
4) Have you seen any company accounts?
This may be basic and already known to you but just in case... Management companies consist of owners in a development. Where the dwelling is an apartment, the managing company owns the apartment and is responsible for the upkeep of the building. If you own a house, it is probably only responsible for the common areas in the development (e.g. greens) not for the externals of your house.
Managing companies only source of income is in the charges they levy on their constituent members. This is used in several ways including day to day expenditure such as getting the green cut or getting flowers planted and for more long term needs such as perhaps painting external walls and fences or replacing gates. It is a depressingly familiar problem that people decide for various reasons to withhold their management fees. This results in a shortfall in the income and may result in a reduction in services or a complete cessation as the managing company does not have endless reserves of cash, or sometimes any reserves of cash to cover this. It can also ultimately result in the bankruptcy of the management company (the managing agent, whom many people equate to the managing company is just contracted to the managing company and usually takes their fees first). Where a managing company goes bankrupt, this will cause difficulty in selling a property (particularly apartments, as this makes simple things like getting building insurance problematic). A good solicitor would check that the managing company is in place and functioning. While it may not mean that the property is completely unsaleable, it will most likely decrease the value of the property.
I think the first thing you need to do is establish that you are part of the managing company. Then contact the agent and request the accounts. Get in contact with your neighbours too. Then you need to look at calling an EGM to discuss this.