Upvote:5
You should contact Iran Air and remind them of your rights and their obligations under the EU Air Passenger Rights Directive:
in the event of a delay longer than three hours, passengers should be offered reimburs*m*nt within seven days (and, if necessary, a free flight to the initial point of departure) and compensation as in the event of cancellation
http://www.europarl.europa.eu/atyourservice/en/displayFtu.html?ftuId=FTU_5.6.2.html
Should Iran Air continue to avoid compensating you, you should lodge an official complaint with them, using the EU Complaint Form.
Should Iran Air still avoid the issue, you then send a copy of that complaint to the relevant national enforcement body of the EU Member that you flew out of (Italy).
Using a third party claims company is pointless because they literally do not do anything more than you would do - they submit the paperwork required. They won't chase, they won't follow the case up, because all of that cuts into their pay - you have literally signed away a portion of any compensation for no benefit at all.
You should check your agreement with Resolver.com, because its highly likely that you have to pay them a portion of your compensation regardless of whether you receive it because of their actions or not once you have engaged them as your agent in this matter.