Vox - where are they?

We decided to Change ISP in order to have a more reliable service - when power is down, the cell towers are "dead", and we only had speeds of 2-7 Mbps (we signed up for 10 and initially had up to 80). We went with VOX / Frogfoot as their advertising shows promise and they are the preferred suppliers in our area. It took 6 weeks for Vox to get the information correct on the application form - the info was pulled in from somewhere and was all old. Each time we corrected it, it defaulted to the old info. Before we signed up, we requested a house visit and survey to determine if we could receive the full 50 Mbps service. Vox came and selected a position in the house. Before Frogfoot installed the cable and connection, we requested a full survey which would guarantee the full service. Frogfoot surveyed and changed the locality of the connection (there was no power supply where Vox had determined it it should be) as it was not suitable. The cable and connection was completed - a very neat job done, and we signed off - note, not knowing if the coverage was correct yet. Vox then fitted the router and we signed off - tested at the point of the router. We then determined that the connection at the home office (the most important reason for the fast fibre connection) was not the full 5 Ghz, but only 2 Ghz, and speed was compromised and erratic - 6 - 80Mbps. Sent a complaint 17/11 We have complained, the Vox Engineer came 22/11 and tested and agreed that there is something wrong, and since then, nothing - promises of action. Heard nothing further and complained again - ticket confirmations but all show and no go! : VOX***8 Vox says 24 hr response, but this is now almost a month since installation, and of course, the Debit Order goes through!! I am back with my old ISP on LTE as it is at least connection, albeit slow and we pray for no power cuts!!