Legally, you must be given a contract of employment stating the terms and conditions of employment within 2 months of joining.
Also, without payslips it would be difficult to know what the deductions from your salary are for, and the company cannot make deductions without telling you.
I assume you got an offer letter before you started telling you your salary, working hours etc etc? This would form the basis of your contract.
You have a lot of issues here with this company. Personally I'd get out now - but make sure you get paid for any time youve worked.