Paying for 5G yet they have kept me on 4G

Ive been trying to have these guys (rain) to fix my connectivity and they have blatantly ignored me. Im on 5G One yet my router is consistently on 4g and yet they bill me for 5G. Now and again videos on YouTube buffer downloads can also be extremely slow. I ve sent numerous messages on their site and they never respond. Im pretty much tired of this company and its incompetence.