Hello @Amrik3
Firstly have you read the extenuating circumstance policy for cancelling under the corona virus https://www.airbnb.co.uk/help/article/2701/extenuating-circumstances-policy-and-the-coronavirus-covi...
Your host is correct you cannot cancel automatically as your travel sits outside of the dates covered by the policy.
Not quite sure what you meant by saying you couldn't get hold of Airbnb? You can reach them by phone, on their social media and online (see Contact Airbnb post at the top of the forum you are posting in.
It is not true to say that you cannot travel anywhere until 5 July. There are plenty of places you can travel to. It is just that STRs are banned in the UK until 4 July
Just give Airbnb a call and explain the situation if your stay is in the UK and ask them to help you cancel penalty free.