I had the same frustration with Abby, but it has gotten so much better!
Hang in there. Abby just turned 6 months old and she's been a lot better the past couple months.
One thing that worked for me was to put a handful of cheerios in my lap with Abby and let her have at 'em while I was brushing her.
You can get a dematting comb for those matted spots. I love mine. I bought it on ebay, but I'm sure you can get one at petsmart too.
Do you conditioner her hair when you bathe her? How about a detangler?