The employer gives more responsibilities with the same salary. What to do?

Dear sir/madam,

I am working as a cashier in a spare parts store, but my owner gives loading and unloading work permit to me. Is it legal?

I am working 11 hours per day without an overtime salary. The accommodation current bill is deducted from my salary and also the internet.

The food expenses are not given so my salary is not enough for me.

What are all my rights?