Poor signal and cistomer service

I stay in springs the pole is in my yard i was said that i will get a 1 gig line because its in my yard and after a year my line was put to a 500mbps line. I compaint via mail a few time my line speed is 16mbps at night and 28mbps at day. No one repies my mail or is prepaird to solve my problem. They know when and how much to take of my account but no sercice from them