Worst customer relationship ever

On 22 July 2015 Smart Blinds & Decor installed blinds at our home. I was at work at the time, the arrangement was made that I would pay them via EFT and send them proof of payment. I made the payment the same day, 22 July, and send proof of payment via e-mail. Today, 23 July, Rita called my mother-in-law(she had her number, as my mother-in-law had her blinds installed by this company, and she accompanied me to their shop), and queried about my payment. It was such an embarresment for me, I called and spoke to Theunis, demanded an appology, and questioned him about the proof of payment I sent to him. He said that he did not have time to check his e-mails, and that he will get Rita to appologize. But Rita refused, yelled at my husband, telling him she did nothing wrong, and it is her right to call family members when money is outstanding. Note that I paid this company on the very same day they did the installation, they do not check their e-mail, they call my mother-in-law in stead of calling me(Rita said she did not have my number???), and then refuse to appologize? Worst worst attitude I have ever encountered.