FINISH VODACOM CONTRACT BUT STILL DIMANDING R3598

Please help i had 3 contract lines with Vodacom, and i finish paying the contract in 17/10/2013.i paid the mount of R170.00. after this amount i have not hear anything or even receive anything from Vodacom , <br> no statements nothing , up until last year August 2014 i was recieving some call from a guy called THABISO PHALA he said he is from some ATTORNEYS COMPANY with contract no *** he was telling me that i owe Vodacom and i must pay the account via them . <br> i thought its one of the ****s because according to my understanding i finish paying my contract .so i went to Vodacom in TIEKAMS CELLULAR where i took out all my contracts and ask for assistance . the consultant there NATALIE phoned vodacom to check if i owe them or not but all the dept confirms that they cant pick up anything with my id no the contracts are deleted and they never say that there is and amount i still need to pay as i said no statement or balance fro 2013. suddenly on the 2/05/2015 I receive a letter form the attorney requesting R3597.35 .i didnt know that i am owing Vodacom now i feel like i will be paying for these new people that are using the numbers now please explain cell no ***its urgent