Underground Cable

We had our cable buried a few years ago but I just noticed that our email says temporary cable. I would like to know when will we get a new cable to replace the temporary one. Also it was buried during the winter time so the person who did the job couldn't get it deep. My husband checked how deep the cable was and it is only 4-10" deep. It is my understanding that the cable is supported to be 18" deep. We are having our lawn worked on our yard soon and would like to make sure the cable is deep enough and also marked for the people working on our lawn.