In arrears for the Contract i never took

I ordered a Router from Vodacom and upon realising the terms and conditions for that contract, I returned the router within two days and the router was collected on 14 July 2017. I called Vodacom informing them that I am no longer taking the contract.

I was informed that the contract will be cancelled within 7 days. today is day 34 and no response but calls for me to pay the arrears amount.

I have since been receiving sms and calls indicating that I am in arrears of R247.81. Upon inquiring, I was told that the back office is investigating this matter. but still the same Vodacom keeps calling me to pay the arrears amount.(talk about system integration)

Now that I am gatvol(for lack of better words)I called Vodacom to cancel my current cell phone contract, and guess what it cannot be cancelled because I am in the so called ARREARS.