Cuckoo has a new home. Your broadband hasn't moved. — find out more
Last updated: 28 May 2026
We aim to provide a great service to all our customers. However, we understand that sometimes things may not go as expected. If something has gone wrong, we want to hear from you so we can investigate and put things right.
The quickest way to raise a concern is through our support channels, where a member of our Customer Experience team will be happy to help.
If your issue has not been resolved through our Customer Experience team, you can submit a formal complaint by emailing us.
Email: customercare@cuckoo.co
Alternatively, you can write to us at:
Onestream Limited trading as Cuckoo Broadband
Unit 15
Fulcrum 2
Solent Way
Fareham
PO15 7FN
Your complaint will be handled by our dedicated complaints team, who will investigate the issue and review the details you have provided. You will receive a response within 7 days, although we will always aim to respond sooner where possible.
If we cannot resolve your complaint within 6 weeks, or if we reach a point where we are unable to agree on a resolution, we may issue what is known as a deadlock letter. This confirms that the complaint has reached the end of our internal complaints process.
At this stage you may refer the matter to an independent dispute resolution service. Onestream Limited trading as Cuckoo Broadband is a member of CISAS (Communications & Internet Services Adjudication Scheme), an independent service that helps resolve disputes between customers and telecom providers.
CISAS contact details