Poor network, poor client service

Been having issues with a slow 5G connection for the last 2 weeks. I lodged a couple of complaints about this with them, they can't be bothered to respond to any of them. I believe the issue is related to the network being congested as the issues mostly occurs during work hours. I switched to their 5G to get away from there ridiculously slow and unstable 4G, now I am starting to experience the same problems with their 5G. But in the last 2 days both myself and my wife got multiple emails and calls from Rain asking if they can sign us up to their 5G that we are already on. How can you put so much effort in to signing more people up to joining your already congested and slow networks, and not be bothered to put any effort in resolving these issues first? Should have heeded the endless warnings online about how horrible this network is.