Policy Bazaar — fraud in term insurance

I purchased a term plan for my wife on 16-jun-2019, keeping in mind that 17-jun is her birthday and premium will increase.
However, i successfully purchased my policy from policy bazaar with help of their executive and followed the instruction given by him.
After buying the policy, each day they were giving me update that everything is in place and the policy will be issued soon.
Suddenly, after 4-5 days, they call me and tell that since the proposal form was submitted after 12:00 am and day was changed so i will have to pay the increased premium.
I clearly told them that this is not my fault as they didn't tell me at the time of purchase so it is their responsibility and they will have to bear my loss.
I am following up with them from last 10 days but they are not doing anything on this matter except saying that either go for cancellation or accept the updated premium.
I opted them for a service and they failed to provide that and now imposing their poor service results upon me. This is not a matter of one time payment, i will have to pay this till the end of policy.
I am unable to find a way forward. Please help in getting this matter resolved.