Request for help against Telkom

I bought a pocket router from Mondo and they delivered Two instead of one. Made an enquiry before using the one i needed and they made it clear that i would only be billed for one and a return address would be emailed for the other. upon receiving the first bill i called to enquire why i was been charged for two when i specifically made it clear i could not afford the 2nd one that i did not request. Decided to cancel the entire contract and Mondo accepted and sent through a cancellation reference. Thereafter a year telkom contacts me about me paying for the 2nd router that i did not ask for and tell me that i owe 2700 in unpaid expenses. When i contact Mondo they say the 2nd one is owned by Telkom and they are no longer in partnership with them. when i asked why didnt my cancellation apply accross all platforms since i made it while they were still in business they assured me to rectify the mistake and not to worry. Now im in debt for R2500 according to telkom and i have been blacklisted. The lawyers are very rude and tell me that i must pay for inserting the sim in the router though data was only loaded for one month and never again. i have evidence of the payment and cancellation reference but my life is been made difficult by a bunch of greedy corporate savages that have no adherence to corporate law. Please if anyone can help me reach out to me on *** or ***. i have no issues turning this into a lawsuit if it means getting my financial freedom back. this is making my life a living hell