some compnaies have these type of policy where they do not provide salary slips ti their staff.
FYI - I am working with a pvt ltd firm which is a sister concern of a huge parent compnay but to my shock I came to know step by step that here there they do not practice for salary slips, formal appointment letter, confirmation letter, appraisal system, mediclaim or insurance, proper leave system etc etc.
Anyways as if you have joined the firm, now learn, grow, increase your capabalities for atleast a year then look out for a good company and confirm them in prior about these things.