Under the Payment Services Regulation 2009 lloyds Bank is liable to you for the correct excution of a payment instruction, unless thay can prove to you and where necessary, to AIB in this case, that AIB actually received the funds. If Lloyds can prove that AIB received the payment then AIB's becomes liable to you. If Lloyds are liable, in that they cant prove that AIB received the funds, then they should refund the full amount and restore your account to the position it would have been in before you made the payments. Contact Llyods, quote the Payment Services Regulations and ask them for proof that AIB has received the funds. If they provide the proof bring it to AIB and demand your funds.