Contacting TPC about defective product

I got my son a Sword & Shield Ultra Premium Collection for his birthday in 2022. He opened it and was missing the coins, but had 2 sets of the black dice. I contacted customer support in April 2022. They said to return the dice and they would send the coins, but didn't have a timing estimate. I followed up every 6 months or so and they always said they are still working on it. Until this year, they don't even respond anymore. Is there a way to elevate this? It's been over 3 years since I first contacted them.