no internet

No or hardly any internet, I have complained for the last couple of months numerous times, Every time I complain it is the same old story; "the link is running well on our side and data is being pulled there, Im going to upgrade your software and then then reboot" Then magicly we have internet again! The last time they came out to test my internet the guy said to me that I could only use one device effecient at a time, which I think is bull****, I never had this problem in the beginning, we could use more that one device easily, Ive got an uncapped 6 terrabite package but most days I cant connect to nothing. Last month I send them an email that I want my package terminated, i didnt even get a reply.