Hard inquiry

I purchased a phone yesterday and was assured by the sales representative multiple times,and the manager of the AT&T store also assured me multiple times the purchasing this new phone WOULDN'T be a Hard inquiry on my Credit report, multiple times I was assured that it would only be a soft inquiry upon my credit report. However 3 to 4 minutes after proceeding to move forward with my purchase I received an alert via credit monitoring that I have a new Hard Inquiry upon my Equifax credit file. This this inquiry on my credit report is going to severely hinder me from moving forward with major purchase loan that is in process at this time. It would be greatly appreciate it if someone from corporate office can help me to rectify this life altering blunder that has been placed upon me unwilling. It would be greatly appreciated if someone would contact me expeditiously to make right of this wrong.