Very very mad customer

My occupation is in the automotive industry im a mechanic.anyway i had a client 3 weeks back i was helping him with his car and when i was finished fixing his car he made a immediate payment into my capitec acount.and the next day the money was out of my account the client went to the bank and told them he has sent money to the wrong nr and so without even calling me or snything they putted the money in unprocessed transactions i went to the bank and showed them my proof that i did fix that car but still nothing and it is another 2weeks that went buy and still nothing or no response from capitec.i use this account everyday for my bussiness and my question is how are my money secured if they just take what they want when they want to.its ***** its just like i go and buy myself a car pay the money into the dealers account and go the next day to the bank and say stop i made a wrong payment and they just believe me and take it from the dealers account and not even let him know so when check his balance then he doesnt have a clue where the money went that is what happened to me.so im not sure if i can go to the police or the hawks to investigate because my money is mot save in my account