Insurance/possible legal issue?

Might have a bit of a legal issue coming up 😂 sorry about the following long story lol;
I got my renewal on xmas eve from coverinaclick.ie for 1220 and I was meant to have windscreen cover and no claims bonus protection. So I paid my 277 deposit, and when they sent out forms to sign, I had neither, and told me I need to cancel and renew again. He told me I couldn't cancel until I get my insurance cert and post it back.
So I posted all signed forms back, to get my insurance cert. To cut a long story short, after 30 days of insurance I still had no certificate of insurance. I kept ringing and they said they didnt receive forms that I have sent. So after 33 days of insurance, I sent a handwritten letter to cancel.
They then told me that because it was over 30 days, they told me I needed to pay an extra 131.99 for another months insurance on top of my deposit. I tried to tell them the only reason I never cancelled sooner is because I was waiting on my cert to post back, and they started to argue that they DID post it.
I'm now insured with Liberty Insurance and all seems to be sorted, until they sent me out a letter saying I've 14 days to pay or they'll take further action.
Should I pay it or see what comes out of it? Theres more details to the story that I left out to keep it short lol. I was only insured for 33 days and already have paid 277 euros.
Sorry again about the novel, and I hope someone can help. Thanks