Cell phone call on my landline.   No message left.  Number has been blocked cell phone

I have rec'd calls from this number since my first report at 15 minute intervals  1:21,1:36, and 1:51 pm.  Apparently from colorado.  Guess they have not figured out that the number has  been blocked

Since my elder parents are in Colorado for vacation and this phone call id said CO, I answered, afraid that it might be a hospital.  Some foreigner on the other end of the line trying to sell me something-I don't know what-and told them to remove me from their call list, don't call back-that I was not interested in what they were trying to sell.