Vodacom account

My grandmother of 66years old had a contract taken out at in 2013 at the Time she was still working and able to pay without fail. She was suddenly retrenched from work and now lives on a pensioners grant. She called in in December of 2014 to notify Vodacom of this they stated that she didn't take out insurance to pay of the contract in the event of retrenchment so she has to now pay off the contract regardless of the fact that she is now a pensioner. Vodacom issued an account number that was invalid so upon paying my grandmother encountered numerous problems Vodacom then threatened her with blacklisting. The account was then handed over to vvm lawyers due to the arrears on the account and interest has been incurred. How was this the clients fault as she was issued incorrect details. Not only is she a pensioner she now has to pay thousands of Rands in interest due to Vodacom employees not issuing correct information is this how we go about treating the elderly?