Can't change products - an error has occurred

[#1]

I see the following message in my account...

You can't change your products for the moment, our system may be updating. Please try again later.

I first noticed this at least a month ago when looking into upgrading to fibre. 

I also just noticed that bills don't appear to be getting generated, or money taken from my account.  The last bill was a year ago, which was around the time I moved house.  Am I likely to get a backdated bill for a year's worth of broadband?

[#2]

Hi@mrjmitch 

No, just for three months

Dave

[#3]

Hi @daveplus 

Thanks for your reply.  Do you know what's likely to be at the root of the problem?  Having to work from home now, I'd quite like to upgrade my connection, and have been watching my account for an opportunity to change my package for a few weeks - whatever's wrong doesn't seem to be a temporary issue.

Thanks,

Jonny