i have a previous case too.. but its the other way round meaning seller void the warranty himself and the phone spoiled.. i took back to its dealer and they said its been open before and warranty is void.. yet he stated that the warranty is still intact so he refund

nothing to do periukman as u void the warranty urself// really u shud complain to seller when ur phone got problem and thus seller is held under responsiblity// in legal way.. seller is not at fault now, its up to the seller whether she wants to pay half of the service fees, its purely optional to the seller but she can maybe offer some compensions? perhaps?