Terms & Conditions of yellow only HERON Group vouchers €50 voucher You can redeem this voucher exclusively by calling 18 228 (HERON Customer Service). The voucher can only be redeemed by a HERON customer, or upon registering with HERON services. The credited amount will appear to the next HERON Electricity Bill. The offer applies to the Interconnected Electricity System (Law 4001/2011) and Crete. The amount of each voucher cannot be exchanged for cash or other vouchers. The voucher is valid up to three months from the date of issuance. The voucher will not be replaced in case of loss or theft. The voucher will not be accepted after the expiration date or replaced by other vouchers. For more information, call 18 228.