@tryingtoohard, Pamela, If under warranty this may be info. needed. From RCA site (1st link) below. RCA North America, Android & Windows Tablets Phone: 877-252-6873 / 800-252-6123.
If you know the chargers are working correctly and the charge ports look clean inside(no dust/lint/debri) and charge ports look good no damaged pins/loose, the issue may be quite simply faulty batteries. In case you would like to try repair your self or another family member/friend, I have posted a disassembly guide(2nd link) and possible replacement battery(link#3) which you can do a search on for possibly better pricing(ensure replacement battery is correct for your model#). A good local computer repair shop may also be a viable solution if not wanting to attempt repair. Good luck. I hope this helped you out, if so let me know by pressing the helpful button.
http://www.rca.com/support-products
[guide|56082]
http://www.ebay.com/itm/RCA-7-034-Genuine-Tablet-Battery-Model-RCT6773W22-P-N-MH49370-/301838252045