Was on Blast, now without my knowledge on Performance Starter

Have been on Blast or the 64.95 + 7.00 a month internet plan for years now. All of a sudden I experienced slow internet speeds and downloads. Being a Comcast customer, I do weekly speed test, for months now, was getting about 30-50 Mbps before....always. Now getting regular 3-4 Mbps download speeds. I signed in to my Comcast account and found out I now have the Performance Starter package. I had no knowledge that my plan changed or was downgraded??? The best part is that I am still being charged for the Blast plan. Any help?? or do I cancel and take my take my business elsewhere....