Why is this ebay seller calling my phone 4 times a day? Is this harassment?

I tried buying something from an ebay seller who seems credible, but 13 days went by and they never delivered my package, and I did notify him after 7 days and he said it was normal for it to take that long (even though I have received packages from california in 3 days). So I asked for a refund and got it. Then, the day after they asked for me to revise my negative response on ebay, and I did, but I left it still negative. Then, the day after, they called me 4 times. The next day, they called me 4 times again! The next day, they called me 3 times, and today they called me twice! I don’t want to pick up because I feel like it is over and done with. I got my refund and they can move on themselves. So wth? Why are they calling me so many times?