Mondo Telkom Bogus company or not???

I took out a Telkom data contract with Mondo in January 2018, as I gave them my details, we agreed for them to debit on the 15th of every month as that is when my salary goes through. To my suprise, no debit from Mondo went through on the 15th of Jan. 2018, I called the number they gave me, but no one answers, I then tried calling Telkom and they unfortunately could not assist me as I need to deal directly with Mondo. Then on the 15th of Feb and March 2018 again no debits went out from my account and I lost that simcard late February and tried calling them again to no avail. I gave up thinking they are probably a bogus company as I cannot get through to them. But now, as I perused my statement yesterday (28th March), I saw that they debit my account on the 30th of every month. and I fail to understand who did they arrange with to debit on that date. My greatest worry is what those missed payments will do to my credit score. I took that contract in order to have a credit history since I was unemployed for a long time and getting approved for credit was hard and not necessarily because I needed it. Since I cannot get through to you people, please be so kind and contact me to resolve this issue.