Greece is available in Adyen but was still defaulting to Ingenico, this was because we had explicitly added countries to the Adyen supported list and ones not in it defaulted to Ingenico.
From a previous task I had looked into:
| Country | Code | Currency | Adyen | Ingenico |
| Slovenia | SI | Available | Default | |
| Azerbaijan | AZ | ? | Default | |
| Albania | AL | Default | ||
| El Salvador | SV | Default | ||
| Ghana | GH | Default | ||
| Zambia | ZM | Default | ||
| Puerto Rico | PR | USD | Default | |
| Guernsey | GG | Default | ||
| Haiti | HT | Default | ||
| Vietnam | VN | Default | ||
| Taiwan | TW | Default | ||
| Northern Mariana Islands | MP | USD | Default |