New Xfinity web e-mail

Hi, This may be a little hard to explain. 2 weeks ago I got an e-mail from a relative from his G-Mail account.  I then deleted it. But every day I get any where from 4 to maybe 12 of the same one. they don't stop coming.  My cousin has deleted everything in his G-Mail and is now using Verizon but I still get them.Have even marked them as Spam but they still come.  I'm at a loss as to what to do next have tried several things. Can you help please?