Need Negative Stara

If i could use negative stars I would. Our flights were cancelled, by the airline, as were all their flights out of Glasgow.
This was due to corona and the restrictions applied to UK citizens into USA, as a result.
I tried to contact Lastminute and they made it impossible, their “customer service” lines were only playing recorded messages and there was no response to any emails, even those sent to their Italian Directors.
This was a package holiday and therefore entitled us to full refund within 14 days, per the Package Travel Regulations.
Their website cancellation process involves you requesting a quotation for cancellation, not allowing for full refund per the law.
I eventually found a working phone number and they refuse to give you any details, any supervisor contact and just keep reiterating that we would receive an email shortly with a quote.
The regulations are clear that the contract is between me and them and they are responsible for my refund, they refuse to acknowledge this and keep stating that they need to get the money back from their suppliers first and this could take months!
I have reported them to the CAA querying their suitability for ATOL certification, given ATOL certification gives people false confidence in these people.
I am now waiting to hear back from credit card company to pursue a ‘chargeback’ claim.
Do not, under any circumstances, trust this company with your money, they will not honour the law, let alone their ATOL certification and, if anything goes wrong you’re on your own!!