Insurance premium increase of 20%

I took a motor and household insurance with dotsure in August 2019. I chose them amongst a number of other insurers with reputable customer service, because of their reasonable premium offered. Can I mention that I'm a 38 year old female, with a claim free history, and about 15yrs driving experience.

End of October I received a review letter from dotsure that my premiums will be increased by about 20%. No reasons noted, just notification of increase. I sent a number of emails to the different email adresses provided, requesting an explanation, but to date non of my emails have been responded to.

I fail to understand why I would get an increase when:

1. I'm working from home since beginning of lockdown, meaning my car is in less risk that before. 2. I have never claimed once since I took the policy. 3. The car is depreciating in value.

Please can I have this clarified before the next debit order goes off so that I can decide whether to look for another insurer or not.