UK Car Repair: my corsa c shudders wen i reach 60 mph...., blow torch, brake cable

Question
hi i just got my mot done so it woz relly only 2 track rod ends & a hand brake cable renewed. so wen i left the garage i turned the first corner and the back end sliped away a bit so on my way back to the garage the steering woz all over the place felt loose & very sensitive (hard to control) i told him and he put it back up the ramp then they wer at it with (blow torch heating device) then drove off fine. went to work the next day on the moter way and soon as it went 65-70mph it instantly started shacking and u could hear and feel the s/wheel & steering column shudderd bad it woz rattling as if sumthing woz going to shake loose it woz that bad. then under 65mph fine.....? it woz fine before he put the new parts on. so i went got the tracking looked at it woz fine but balance woz off a bit so got that fixed(another garage mite add) now it starts again wen i get to around 70+mph and gets worse the faster u go. it feels unsafe a little slidy wen turning but?? a dont know wot to do or wot the problem can be!! i would be very greatful if you could lend a little expert advise on wots the problem? thank you

Answer
Please do not drive the car, other than to get it repaired, clearly this is something to do with the first shop, give them one more chance to rectify it, if they can't or wont, take it to a reputable mechanic and warn the first shop that you will be billing them for the repairs.