Scratch Screen happened by it self???

Got new phone. Could not use it for a month since sale staff never told me I would need a micro sim. Then finally tested the phone just for good measure using my tablet sim. Phone had Battery issues. So I took the phone to get repaired. Got it back in like 2 weeks with a scratch screen . So I refused to accept it. And lodged a complaint... response was that when the phone was booked in it had a scratch on it. This is a complete lie since it is a brand new phone... documents they show me where I singed I did not indicate any damage yet what the sales staff did after i left was book the phone in that it was damage.. after 2 months of dealing with customer complaints still nothing has been done and it seems Verna in her last email gave me a rude and unhelpful responds that indicate they will not be doing anything and I must accept the matter as resolved and the damaged phone. This is not only upsetting or made the whole proses even worst but is against the consumer protection act. Very unhappy... would like any advice if some one can help?