I have found there are 2 companies, I am slightly confused how it works, can anyone give some clear it up. Do you use both companies depending or just use 1. If using 1 , is one company better than the other
Do you mean two different schemes?
1. Some merchants accept the Horizon card which is much easier for the buyer. Ask the merchant for one at your first purchase. I think your refund is loaded on the card and then when you get to the airport you insert it into a machine and fill out the information asked for. Your refund is applied back to the credit card # you type in so make sure your numbers are accurate.
AND/OR
2. Some merchants will fill out their section of VAT information on your purchase receipt as they do not use the Horizon card. It is your responsibility to complete the bottom section of the receipt with information like name, passport #, address, and so on. This takes a bit of time, so have it ready before you get to the airport. Your take your receipts to the VAT kiosk and give them to the customer service person there. Your refund will be posted to the credit card you indicate on the receipts you completed.
You fill out the Horizon refund information and turn in your receipts at one kiosk. If you miss the VAT kiosk or run out of time at the airport you can mail the card and receipts back to Ireland. The kiosk is well marked, however I have managed to miss it a few times. Merchants hand out the mailing envelopes so just save one or two in case you need to mail your receipts.
I hope this helps.