Undermining customer

I went to Westgate MTN to renew my contract. I requested an IPhone 7plus Rose Gold. They checked the availability and Cresta had that. An email was sent to Johan to keep that phone. I was told to come any time after 9am. I went this afternoon to finalize the contact. To my frustration I was told that Cresta sold the phone today. As a client I feel I was disrespected and undermined. If a request is made the shop cannot sell the phone. This is the second time I get such a bad service from MTN. Are there people who are more important than the others. As MTN old client I am very angry with this type of service. I feel like leaving MTN it's becoming a norm to disrespect clients. I am Joy Legodi-Zimba. My contact details are ********** 616. Email: joyzimba ********** com