BEYOND FRUSTRATED!!!

I had a data contract with Vodacom through Nashua Mobile.i went overseas in 2014 & ensured that i completed the correct paperwork to cancel this contract on the correct date as i was not going to be back in SA in time. Nashua Mobile closed down & my paperwork was NOT submitted.I didnt know this.The contract was due to end Dec 2014.I emailed the Vodacom customer care many times in Nov 2014 RE the status of this cancellation(i was home early)& only received a response late Dec 2014.They ensured me that my contract would be cancelled & NO further fees would be charged.I have a letter from them stating that my contract has been cancelled.I believed this matter to be settled.BUT Vodacom dared bill me at the end of January 2015 (R 199.00) for my data contract.NOTE:I didnt use data as i had no internet connection!i went to the store many times to sort this out.i have copies of all paperwork to confirm it has been sorted & I was promised that I would be refunded this money within 48 hours. This was on the 12th Feb 2015 & STILL HAS NOT BEEN done.When I phone I am told to contact their legal deptartment.This is ridiculous!!!