Bad customer service and incorrect billing

I'm the month of May I have paid twice the subscription. On the 29th I paid 535 and on the 6th the went and debited again on my account. Mid month of May I asked them to change my debit date to be the 28th as I get paid then but they said that they can't as their system only has 3 dates 1st, 25th and 15th of every month then I took the 1st. To my surprise they went in to debit on the 25th after I spoke to them. So on the 29th I decided to pay them via the app. Now come the 1st June money was deducted from acooubt and when I query this they would fight me and they would put the phone down on my ears twice. So I thought maybe month end I would be have a credit of 535 then I would pay the 84 difference but that is not the case. No one has contacted me up until today