Switched charger damages charging block

Good day, very disappointed in pnp hyper in ottery. I bought a cordless Ryobi cordless 18v drill for R999. 00. I only used the drill 1 - 3 times. When the battery went flat I charged it with charger provided inside of the box. The charger in the box was not the original charger Ryobi issues with each drill. So the charger was switched before I purchased the drill. The charger was not the correct charger in terms of voltage and has in fact damaged the charging block. I called Ryobi repairs and was told to have the issue cleared with pnp and having the block and charger replaced costs about R1050. I am very sad and disappointed as we purchase from pnp frequently.