Has any else had a big problem with Mr Tire?

I bought 4 new tires about 2 years ago and have about 20,000 (if that ) on them. And there blowing one after another 2 in 4 months. Everyone is telling me that a $20.00 credit on my $120.00 tire is normal for the road hazzard warrenty I feel like I am being taken and the should do more? What do u think? also the tires are good years 50,000 mile tires!!!|||id talk to them. you should have gotten 50000 miles out of them. also do you have insurance or some plan for them