MTN will not exchange faulty router (3 months old) due to missing box lid

I signed up for a data-based contract with MTN in August, which included a Wi-Fi router. Within 3 months of use, the router stopped working. MTN claims that it does not fall under warranty as I did not return it in its original packaging (the box lid was missing). From the reading that I have done, this is in contravention of the Consumer Protection Act which states that the original packaging does not need to be provided for a defective product within 6 months of purchase. I also read through the MTN after sales technical Ts&Cs and nothing is mentioned about original packaging and returns.

I am now sitting with a data contract that I can not use. Really disgusted and frustrated with MTN.