here some of the local sponsors know that you cannot change your sponsor or company.  Hence they do not bother about increments, or even if there is an increment, it is insignifant.  It is like, take it or leave it, and if you leave the country, you cannot come back for 2 years. Sometimes you cannot leave as you need an exit to leave the country.

You can complaint at the labour department, but who wants to rattle the system or grapewine that gives you your allowance every month.