terrible service and lack of understanding

My cell phone couldn't receive calls for a week due to an issue with their services and after the first time I went into the shop and spending over an hour of my time they promised the issue would be resolved. The issue persisted and I lost valuable business due to the fact that suppliers couldn't get in touch with me. The second time I went in the shop assistant couldn't find my details on the system and eventually told me I'd been blocked for no reason at all. I asked for some kind of compensation after having to try and phone multiple contacts and let them know I was having issues with my cell phone provider, they let me know that there was nothing they could do. I have absolutely lost confidence in them as a provider and I'm considering cancelling my contract after being a client for over 20 years.