Blackberrie 9720 contract and handsets give endles

Ive got two cellphone contracts and received two 9720 handsets from Vodacom. Both cellphones broke and was replaced with new 9720 handsets. I booked the one new handset in again as it doesnt want to charge anymore. Vodacom called me on my cell to collect my cellphone. When I arrived at Vodacom Menlyn I was told to pay for the damages and that Vodacom refuse to pay. I did not break the phone. The 9720 is commonly known for giving endless problems