If the sewage situation is not corrected ASAP, you could be looking at a hefty fine for dumping raw sewage into the environment.
Have the system inspected. Don't go with an inspector who also sells and installs septic systems. Get at least two more quotes. A permit and inspection will be required for whatever new system you install.
Septic Care: What is a Septic System? How Does a Septic System Work? Why Does a Septic System Fail? What are Signs of a Failing Septic System? It is doubtful that you can go back on the seller. The system worked when you purchased the home. As you say, " Been in this house 5 years. When purchasing, dye test passed, no problems."
Septic systems are designed to process biological waste. Adding gray water waste, such as from washer, to system can overburden the system. Lint from washer can cause system failure. If washer is used, it is recommended that laundry be spread out over several days so as not to overburden the system. In the meantime, go to the laundrymat.
Driveway should never be placed over leach field.
Pennsylvania Septage Management Association :: Septic Care Tips