I worked at a large PD in OH for 25 years and used to take telephone harassment reports on the phone. First thing you have to do is tell them to remove your number and not call again for the calls to turn into harassment. Once you tell them to remove your number, if you see it come up again you have to keep a record of date and time. IF you get several calls in a week or two, then you have to contact the phone company and let them know what you have. They will send you a packet to include your documentation and papers for you to sign authorizing them to put a tap on your phone. Once they have documentation showing the harassment, they will turn it over to the prosecutor's office who will then summon you and the guilty party to their office to discuss the problem. Laws may vary in your jurisdiction so you need to contact your PD and find out what the law says where you live.
What is odd is we live in the Dallas area so 972 would not be out of area.... which lets me know someone is up to no good