| Customer service | 05 7780 500 | weekdays 8–16 |
| Builder’s services and connection matters | 05 7780 510 | weekdays 8–16 |
| Fault notifications | 05 7780 222 | 24 h |
| Contact form |
| customerservice@ksoy.fi |
| liittymamyynti@ksoy.fi |
| yritysmyynti@ksoy.fi |
| firstname.lastname@ksoy.fi |
| Kouvola | Yhdystie 7, P.O. Box 9, 47200 Elimäki | Closed. Please contact us by phone or use the contact form (link above). |
| Kotka | Kotkantie 2, P.O. Box 65, 48101 Kotka | Closed. Please contact us by phone or use the contact form (link above). |