MTN I need my R70 back please

I'm so disappointed and angry MTN are ****mers. I bought a router and l have a MTN sim card that l only use at the end of the month just to recharge for the MTN router l buy R500 airtime that are change to super day 200G so that it can last me for the whole month. It my 3rd month using it but when l recharge today with R500 and try to change it to data it says insufficient funds l was puzzled about this as l just recharge. When l was checking my balance only to find that l have R430 and l phone MTN customer service they told me that l have 2 subscriptions on my phone that are charging me R30 and R39 my question was how come cause l only use my sim card to recharge for the router month end only and l was told that I signed up for one on the 19 and 21 of April. MTN l just want my R70 back please cause this is unfair and wrong. Please show me where l signed and agreed that you can take my money as you please please provide me with proof