You can cancel your Private Mortgage Insurance if:
If you purchased your home after July of 1999, federal law requires your lender to inform you when you loan balance reaches 78% of its original amount.
However if your loan was sold to Fannie Mae or Freddie Mac, you have a much easier road to navigate. These federal secondary market makers have much better cancellation rules than the Federal law.
As long as you have been timely with your payments and your home loan is over two years old, These two institutions have instructed their servicers to cancel the PMI when the loan to value drops below 80%. All you need to do is call the servicer and tell them you believe your loan to value ratio to be below 80%.
The servicer may give you names of approved local appraisers. depending on how much you have overpaid you may be due a nice hefty rebate.
So what can you do?