Can I take legal action against a booking agency refusing to refund airport taxes? [closed]

My friend went to Tokyo earlier this year, booking through getaflight.co.uk

However, due to an emergency, he wasn't able to use the second leg of his return trip - as such he is legally entitled to a refund of the airport taxes of that leg.

However, despite lots of e-mails (which I have saved), they haven't requested the refund from Alitalia in 3 months, and once when I called to ask them, they outright lied by saying that, because one leg of the return trip was used, my friend isn't entitled to a refund of the unused leg.

To clarify, it is not stated in their T&C that a fee is charged for tax refunds.

I sent them an E-Mail with high priority just now, and decided that if they don't respond within the next week, I will take legal action against them if possible.

Is there any legal action at all to be taken against an agency refusing to perform a refund the passenger is legally entitled to?

UPATE: Okaayy, so now I called Getaflight (they don't seem keen on answering e-mails) who said the refund request had been rejected by Alitalia. I then called Alitalia and got a tax refund "specialist" who said taxes are always refundable but that Alitalia never got a request.

I just sent a high-priority message to getaflight, and a copy to Alitalia, confronting them about the fact that once again they're outright lying about this whole thing.