Money disappears, consultant refuses to help!!

I purchased R20 aritime using my cellphone and it was debited from my bank account. My airtime account got recharged with R20 but when I got my bank sms notification, it didn't add up. They said R20 has purchased from my card yet they deducted R40. I called their customer service, as I was talking to Nompumelelo, I asked her, I'm running out of airtime and my querry has not been solved can she plz call me back. She gladly refused to call me back and my call was cut. Now I can't trust standard bank with my money they proved that a customer is not a priority and now I will never get back the extra money that was deducted from my account. This is too upsetting I'm definitely leaving standard bank. They can't even give me an explaination as to why R40 was deducted when I only purchased R20 airtime. This is unacceptable! And I'll make sure that my husband leaves that bank as well.