PLEASE, SOMEONE HELP ME IN THIS MATTER ABOUT MY DAUGHTER!?

I met my daughter's mother amanda in south carolina(my home state), and were together for about 4 years, we decided to move maryland (my baby momma home state), and we lived there for 2 years. During those 2 years we had a lil girl and soon things quickly fell apart between us...mainly because of finances. We decided to just move back to south carolina to get back on our feet. A few months after we moved back to SC, we split up. I went overseas for 6 months and in that time my mother contacted me, stating that amanda simply drop our daughter off at my moms house and she never saw her again. Its like she simply vanished! During that time she would occassionally drop letters in the mail stating that she wasn't ready to be a mom and she still wanted to enjoy life and etc. We found out that she was partying a lot in georgia and didn't want the responsibilities at that time. So my mom had to raise her for the next 4 months. Amanda returned back and took our daughter then ranned back to maryland...still at an unknowned addrress, and I haven't spoken to neither her nor my daughter in over 6 years. I received notices of child support request from a town in maryland that I've never heard of and now I'm in arrears of over $10,000! I don't have a clue of what to do, they suspended my license, taking money out of my check, taking my income tax and I have yet to know where she's located. I don't know what the law can do for me nor trying to find out what can I legally do especially when she's up north somewhere. What can I do? Please help me!