I already have accountant, will he be able to close the company
A real accountant or just a book keeper (księgowa)? An accountant specialising in small firms should be able to deal with registration/deregistration issues of limited companies, however if you just use a księgowa
, in Poland you would normally need to go to a lawyer for that sort of thing. Some might be able to do it, however most do not get involved with more complex tasks for limited companies.
It's very simple to do really - but if you don't speak Polish you will need a lawyer to prepare the paperwork.