GMAC Mortgage Refinance Appraisal Value not real value in order to keep us in a 6.75% mortgage with them!!! Internet

We purchased our home in 2004 for $850,000 (appraised at slighly over $1 Million).  We refinanced in 2006 (appraised at $950,000).  We have a standard conventional loan.  This past August we decided to liquidate assets to come up with sufficient cash to paydown our mortgage to whatever was needed in order to lower our rate.  Zillow (which is always low) reflects a current value of $620,000.  We owe $700,000 approximately and were willing to paydown the mortgage to 80% of $620,000 value if necessary.  GMAC got a complete financial picture on us and knew they could get us to paydown the loan to even lower so they would no longer need to carry a jumbo loan on their books - so we contend they lowered the value of the appraisal (when reviewed internally) to $530,000 in order to either get us to stay in the 6.75% rate or pay down the loan to below the jumbo limits.  They did not deal fairly and honestly with the appraisal because they were losing out on 6.75% rate and would have been giving us a rate in the low to mid 4% range - they knew our financial capabilities - so they took advantage.  If we were to put our home on the market at even $620,000 we would have a line on the front lawn to buy.  We are that part of America that still exists that despite our ability to short sell our home legally or go buy another house and walk away from the one we are in - we chose to live up to our obligations because its simply the right thing to do.  GMAC took unfair advantage.  We also reported them to the CFPB - Consumer Financial Protection Bureau and are waiting for a response on that as well.  I will write to as many as I can about what they did.  Even if it doesn't help us - maybe it will help others.  GMAC should not be allowed to get away with this.  We understand that values have dropped.  We are not disputing this in any way.  It is simply that GMAC did not act in good faith.