First of all my sympathy with you....You were needed to battle strongly and thoughtfully.
You wrote "An amount of Rs. 7500 has been given to the child based on ITR of 2008-2009 and bank statement of 2009-2010." .........(Why did you give old data? instead of current earning capacity?)
Also that "I had given my by ITR for 2009-2010 to my lawyer but he did not submitted. During those period I was in business. During those period I was in business." (Not an excuse...now unless you both come up with excellent cogent reason)
And that "I was doing job for 22,000 from may-october, then rs. 12,000 for dec-jan. now i am unemployed as my mother is having cancer and there's no one at home to take care of her."
And that "In 2010-2011 I was doing job for 22,000 from may-october, then rs. 12,000 for dec-jan. now i am unemployed as my mother is having cancer and there's no one at home to take care of her." (This should have been your main focus areas and stress upon!)
What happened on RCR front?...why didn't you try to expedite it....pressing rights were yours!!!
You could have afforded to continue with sec 24 even after RCR case disposed off, how did it get delayed?
Failure to pay maint may suspend your RCR proceedings and even it may get dismissed. And on top of it maint due is not avoidable.
Go through 'reviw provision' find out lacunas, errors or any other material irregularities happened in the case and file 'for stay' and 'review' in same court withing 30 calender days. else its difficult.
Maint awarded is for Child. wife has been adjudged an able bodied and having capacity to earn. So its almost a water tight case in favour of wife/child...has there been any proofs of expenditures on child by wife? why did she ask for 7500/- for child?
Is there any mention as to 'How did the Hon Court come to conclusion in regards to your earning capacity?'.
Again...................... it is discretionary conclusion ........................ and can be AT THE MAX called ( but difficult convince it now!! ) 'an erroneous application of law to facts', but not failure as to 'Question of Law'.