State Bank Of India — irregular deductions

i have take a loan from S B I, and instead of monthly deductions, the officer in charge pradeep joshi, is deducting the said monthly deduction, in what ever way he likes, sometimes once in 2 months or 3 months, of the accumulated 3 E M I at one time which, is a heavier amount. my request is can anyone instruct him, for not doing like this. regards murthy