Samsung - Mobile Device Display Damaged By Company

I went to samsung service center for getting Network issues so they inspect my device and give me quote of *.*k to change anteena device something my device is working good except network issue so i tell him to do whatever you want and they don't have parts available so i get back my phone my device is samsung fold * so when i flip the phone and close phone got switched off so i return give to them to check why this happening this is not like this before so they check again and took my device for inspection after that the inner display got blanked and not working and now they are telling me to pay **k for display which is working fine and after they see mobile is not working they said need to change battery as well which is also cost *k and they give me quotation of **k without any of my fault after raise complaint with higher authority people they said products of * years old don't have warranty or guarantee and they are not accepting there mistake