Adjustment of Status - I-485

Is 22 days after my interview I received a letter from USCIS requesting me to provide evidence of supporting my children back home in India inform of western Union transfers to them as in child support. But the fact is that I have never send them money via western Union transfers. Because I have landed properties where she collect annual rent of $12,000 equivalent which she is using to take care of my kids/support thus the reason I am not sending them money. Also, I have enough money in my local currency where I transfer money to them occasionally via internet banking, like once in a month whenever the needs arises to take care of my kids. Now the USCIS need evidence inform of western Union which I do not have. please advice me. Thanks I am thinking of explaining to them in a letter and print out the local currently transfers slips plus the landed properties documents to them. please help me I am kind of confused