Terrible signal

Mtn does not improve there signal, you pay them so much money, stay a loyal customer but, they dont improve there signal, my hsdpa doesnt work how it should i live in Colorado Mitchells Plain, theres no use having hsdpa when it doesnt work right, my 3G modem as well, theres no use having a 3G modem if you cant use it at properly, over the years the signal just went from good to worse