6 month old phone keyboard only working sometimes and battery problems

I bought a cellc empire at edgars promenade mall Michells plain on the 28th of april 6 months ago and use it only after 5 everyday and the key touch is starting to give me problems sometimes when i type some of the letters like f,g,h,j,c,v,b,n dont respont when i type also the battery is starting to bulge and only lasting for about 2 hours when in use and i noticed on the warranty slip that you do not cover batteries, i am booking the phone in tomorrow at edgars promenade and i am not going to pay for the replacement battery because the battery max charging voltage states 4v and the charger supp**** with the phone is 5v so the charger is exeeding the batteries max charging voltage i have done my research on this issue and i will attach a screenshot for you to see that when you exeed the max voltage of a battery it gets damaged, i do not want to hear any stories from edcon about cellc not replacing the battery and fixing the phone as i did not do business with cellc please sort this issue out and dont blame me because the battery failed