HELP ! Cam shaft sensors

[Deborah]

Please someone help  , I had my spanner light come on so I took local garage they diagnosed cam shaft sensor fault , they replaced 2 sensors ( 179 pound including labour ) now although light gone off every 3/4 th attempt to start car it doesn’t start then I turn back the key and it starts fine , I been back garage 3 times they just fobbing me off ( I’m a girl ) and saying it’s fine but obv it’s not , I had no starting issues  before and I’m worried continue use will cause more damage … any advice ?