Lenovo — blue screen errors and multiple issues with laptop

Ive been to the service center multiple times for the repair and everytime they say it's fine and i still need to go again i even tried online customer support nothing works sometimes the laptop is with service center for more than 2weeks insipite of doing everything they said and lots of troubles and irritation i'm still having problem with lenovo! Online ppl says that they can only provide limited software support and there is no issue with hardware and for software they can oy install is! Which is not solving the issue! Offline service says that hardware have a prblm and is rectified and it also not and issue still exists i'm fed up with lenovo service is really bad i can't take anymore either replace my lap or need a solution immediately