Sage Online Accounting destroying our business

Our company supply schools. We use Sage Pastel Online Accounting to do quotations and invoices for our customers. The 17th of January 2021 Sage 'Úpgraded' their program and now it doesn't work anymore. This is after Covid 19 lockdown negatively influencing our business and we can't send quotations of invoices to our customers during the time of year in which we do 90% of our business. This is completely unacceptable. It is now the 26th of January and we still can't log in to do business!