MG ZS whines when started jumps in reverse when jumps breaks don't work engine dies and has died whilst on road mid turndies

Intermittent issue. Am in Australia put family postcode and town in UK. Have returned vehicle to dealer several times. Car makes high pitched whining sound when started have to turn off sit then try again sometimes when in reverse car bunny hops then brakes will not work have to use hand brake. Twice has died on me when reversed out of driveway and I was on the road proper with oncoming cars. Died on me while on a main road as I started to turn inti another road with oncoming traffic. Hazard lights came on twice whilst actually driving. Feels sluggish going uphill. Intermittent problem however dealer had vehicle for 12 days last time replaced a part told me it did not do any of the things described by me while they had the car. Twelve days after got it back it did it again 11 days after that did its thing again 12 days after that died on busy road in front of oncoming traffic.