Debbie c123

Hi can anyone help ? 😩 I brought a 12 plate bmw 118 sport a couple months ago - I was sick for 2 weeks when it was really cold and didn’t drive it at all when I came to use it wouldn’t start , called AA said glow plug problem - booked into garage over road , to change all 4 ( 160 cost ) after 2 hours they called to say they changed no1 and no2 had broken - not touched 3/4 could have the car back - charged 16 pound for plug 1 ( no labour charge ) - a week later boss of garage back of hols told me to take car back he’d look at it - called same day to say changed relay ( 220 pound ) and not touched the plugs said would run coke without no2 as it only starts car - I’m a girl with no one to ask advice but doesn’t seem right to me that it’s ok without gp 2 .. car seems a bit jerky when first started ( barely noticeable) I’m just worried I’m causing more damage but can’t afford the 200 to drill out no2 ( even if they can get it out as can cause cracked head ?) any advice greatly received xx