went backwards when it was in drive

I've had my car at the dealership 3 times already this year for transmission and the first time they brought it back in touched but said they had fixed it and couldn't see what the problem was. As soon as I get in my car I immediately called and told them the shaking was worse now then when they took it. They came and got it again this time telling me that their was so much mud under the car theta why it was shaking but they just dropped it off to me and if they had checked the transmission before wouldn't they have seen the mud then. And if they had drove it before they brought tit back to me wouldn't they have clearly felt the shaking and not said it was fixed. The third time they couldn't tell me exactly what the problem was but it was a recall on the module. Now in he 6 th of July I put my car in drive and give it gas when it proceeds to go backwards. I look at my son and say please tell me that's in reverse and he said no its in drive. I try again and when I give it gas it goes backwards then kinda slow motion starts rolling forward. I could have hit someone and this car is becoming very hazardous. I've asked for it to be fixed they say they do but I think they can't fix it and are just waiting on my warranty to expire. It goes back to shop next week.