I hate this network company

In 2018 or 2019 I took a R99 simcard minute contract with TELKOM. the contract was for minutes and I was informed R99 Only once minutes are finished I could recharge .....I repeatedly asked the consultant at the time that there would be no extra charges or other charges for whatever reasons ...so basically I asked him to be transparent with all the fees and extra charges for whatever reason so that when I accept the contract I do no accept blindly...the guy assured and I accepted ...the first few months went by fine debit order off as per agreement...later they started to bill me more at first was due to early debit and I accepted .....then the debit was now R400 THEN R800 when this happened I called to find out why am I being debited this much when our agreement was only R99 the gentle man assisting me at the time could not really understand also and I advised that I wanted to cancel the agreement as it was not honoring what I and TELKOM agreed upon.......they could not find the recorded call .......I no longer used the sim card from the time they started debiting more than agreement but the Charge went on to R1200 after I have called and disputed .........the consultant I spoke to said they will close the account which was closed and showed on my report as closed to my surprise this morning a collection company which I have no dealings with named NUDEBT is sending me an email that they have issued a default judgement against me for the same account...... I have worked very hard to improve my credit score and do my best to honor my debits ....telkom has not called me ever for collections I called them when they did contrary to the agreement and I closed the account now nudebt is claiming that I did not respond to telkoms calls ....please sort this with nudebt and remove that judgement on my name please