I changed my country and debit card and now I've lost all my purchases

Check if the purchases you have lost can be purchased in Ireland. If they can, contact iTunes and ask for an explanation. If they can't, this is why you have lost them.

Nothing is wrong. This is what is expected to happen, and what Apple makes clear will happen when you change countries:

Change your iTunes Store country or region - Apple Support

• You won't see the items that you purchased from the previous country’s store in your Purchased section.
• You won’t see the items from your iCloud Music Library that you matched, uploaded, or added from the previous country’s store.

The Purchases are not actually gone, nor are they removed from your account. They simply cannot be seen while your account is set to the new country.

If you change it back, your purchases will return. You can talk to Apple, but its unlikely anything will change.

did you get any response from Apple about this? i have the same problem. although i can probably just subscribe to Apple Music, but this should be the last option.