Thanks for your posts and welcome back! I have moved your post to the BT Infinity speed/connection board where it's more relevant and where you'll be offered the best advice.
I'm sorry for all the problems you have had getting BT Infinity (FTTP) connected and that your services is now showing a fault condition.
Do you want to have a go chatting with our technical team on live chat to see if they can get you sorted out? You can chat with them directly here: Live Chat
Post back and let me know how you get on.
If internet connection is essential to your work, perhaps you should consider a business line with a proper SLA rather than trying to rely on a best endeavours residential product.
The FTTH team is very hard to get hold off, I had complaint once as mentioned elsewhere and a representative informed me the FTTH crew is a small technical team, I said I don't mind waiiting but good to know where I am on the queue. I once had the FTTC team trying to contact FTTH team on my behalf and they couldn't get through any better than I did.
If you want to contact the FTTH team the morning is the best time. Other times is pure luck.Be prepare to wait and monitor the call on speakerphone till you get through.