Vodacom's new smart tablet

In February I took out a contract for what I thought was an amazing entry level tablet. This is a data only contract which suited me fine. 7 months later the tablet does not want to go on. I took it to the repair Centre in Canal Walk. I received a call back that the tablet's power jack shows signs of corrosion and that I will have to pay R998.00 to replace the unit as the Warranty does not cover corrosion and they do not repair these units. This unit was no where near water as I carried it in my bag in a pouch with me to work everyday and when I returned home it stayed in my bag as I mainly used it for research at work and some games that I played. I explained this to the technician and he said sometimes it is the humidity in the air. AM I NOW RESPONSIBLE FOR THE ENVIRONMENT? I have older phones that is working perfectly fine. I have spoken to 3 other persons that have also experienced a problem with this tablet. I checked the Internet and there was also reports of this tablet being problematic. Is Vodacom trying to get out of replacing a defective unit by calling it water damaged or corroded? in the meantime I am still responsible for paying the contract!!