car accelerates by itself lost control

I had an experience while driving on a 2 lane highway when the car accelerated very rapidly after I took foot of of gas pedal. I lost control and went across 2 lanes & median I was able to steer it at the end of 3 very scary out of control swerves. I was a mess ,nervous wreck & afraid to drive it.

Then about 2 weeks later I parked my car on an incline parking space with my mom in it . I was walking across the Main Street to converse & Someone screamed my car was backing up into traffic & my 84 year old Mother in it. Stopped when it hit a Jeep.

Dealer ,Mechanics blew me off.