Your question provides the answers.
Your old insurer would not renew insurance. These days insurers are being extra tough, and in many cases deciding not to insure buildings, many times for reasons not of the doing of the owners.
That means that any renewal is probably going to be more expensive because insurers ascribe a higher risk.
Ive seen my building insurance go up 150 % in less than 3 years.
And because some insurers are refusing to quote, it’s not possible to get three quotes.
I’d say your building is lucky to get insurance.