Can you give me advise on how to do it?
You should write a 'Letter Before Claim' to Facebook Ireland (IG terms The Instagram Service is one of the Facebook Products, provided to you by Facebook Ireland Limited. These Terms of Use therefore constitute an agreement between you and Facebook Ireland Limited.) This letter should outline your claim and include all evidence you have to support your claim. You can find out more here: https://www.citizensadvice.org.uk/law-and-courts/legal-syste...
If they fail to respond in 14 days you will need to file your claim with the small claims court in Ireland, they are quite helpful and answer the phone and emails. You can find out more here: https://e-justice.europa.eu/content_small_claims-42-en.do