I want my money back

During the month of October my phone just started loosing network didn't work. I went to MTN they fixed it. During that time an amount of R1500 transfered from my account to another Capitec user by the name of MP Mthembu. I went to Capitec they said they will make an investigation after 7 days they called me and told me that there's nothing they can do because its a ***** from MTN. So my issue is the incident happened in my Capitec account by another Capitec account holder so Capitec is fully liable for this and they must be accountable. I want my money back to my account this is an inside job because apparently I'm not the only one who had this done to her.