Recycling Prepaid Numbers

I've been here 3 months already but am still surviving on a prepaid number as I have not decided which phone to buy and what plan to subscribe to. One problem I have found with using a prepaid number is the way they recycle numbers after a while. Recently, I got a few calls from someone asking for a wrong person and some calls from another person who was desperately trying to order Phentermine! I don't even know what Phentermine is but think it might be a weight loss drug. Perhaps that was why the person was so stressed in trying to get some!