@RadioRentalUnfortuantely repairing a mast can take a bit of time, and with Covid-19 stituation this will have possibly delayed any repairs / replacement, and also in getting access.
I would recommend using Wifi Calling if your handset has this functionality.
I would also recommend download the o2 my network app, and reporting the issue on their this will then notify you of any update.
You can also put your post code into
https://status.o2.co.uk and check for any updates.
I also doubt o2 will give you any money back on your airtime, as this is something they can not have foreseen.
Current Phone: Sony XPeria Pro-I and Motorola Razr 5G
I also have a Planet Computers Gemini
I work in IT as an Enterprise Messaging and Collaboration Tools Administrator (Office 365, Slack and much much more) and manage hardware both Mobile and Desktop / laptop, my desk is a bit like PC World
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We are all customers and dont have access to any o2 accounts