unauthorized placement of lines

First, we cannot have legal discussion here, so we will not be discussing whether or not you can sue them, or how, or anything of the sort.

Second, the question about whether AT&T should have placed such a line would be whether the line is in an easement or not:

• Do you know what utility easements affect your property?
• Do you know whether or not this line is in such an easement?

When was this line placed?  Do you know what the line is for?

Does the property have an easement, power, water, sewer, gas, communication all can be placed within easement without notification or permission.. 

If unsure check with local government office that controls easements.

In my state all properties have easements, 15 feet from edge road or alley and 8 feet on either side of adjoining property lines.

I appreciate all the clarifications.  They were not within the boundaries of the easement, they outright crossed my property near my front door and tore up my grass.  

In that case, I'd start by talking to your local public utility commission for advice.