Demand and calim for damages

In May of this year, my U verse service went out and a repair tech came by my house and there was a cable wire on my property that was sticking out of the ground that had been cut. This is a cable wire similar to the one that goes behind the tv. The tech repaired it and the tv was working again, all within 45 minutes. Approximately 1 1/2 months later I received a bill for damages totaling 562.47. I was charged for 8 hours of labor and $6.94 for the cable wire and approx. $15 for a trouble ticket. I contacted ATT and spoke with someone and I explained that there was a serious error in the billing. The tech was on my property for 45 minutes and I can prove it because I have security camera footage both in the front and back. The att rep said it must be a mistake and not to worry (I'm sure there is proof of my call). I soon after received a letter from a collection agency demanding payment. I spoke with them and it was not helpful since all they care about is payment. I contacted Risk Management on a phone number provided on the bill and they were working from home due to Covid and redirected me to the collection agency. I have tried calling ATT to resolve this and provide proof that I was being unjustly charged and no one is able to help. The bill itself is self explanatory since the parts were only $6.94. I've been a loyal customer of att uverse since its inception as well as an owner of att cell phone service. Is there someone that can help investigate this so I can resolve this without it getting any further complicated?