This call is from Southwest Credit Systems.
I called the number back *67 to block my number and it is answered right away with a recording, "Hello, thank you for calling Southwest Credit Systems. All calls may be monitored and/or recorded. Currently, ..." and then someone answered before the recording finished. I asked them which companies they do collections for and the rep told me after several tries that they do collections for ATT, Verizon, T-Mobile and others.