you have a serious problem. it will be unusual for a company to take you on if another insurer refuses to renew. Your previous insurer must know this too. I would write to chief executive asking for a reason for the refusal and also asking him to reconsider as the matter is causing immense hardship. At the end of the letter, I would appeal to him to at least hold you on cover on existing terms or some terms, to give you time to get cover. They might renew with extra terms, such as excluding burglary or imposing a larger excess.
If you have a morgage, remember that the house must be insured for fire at a minimum.