Yep, try 3 days. That's the official limit for most sets, and in the case of a foreign object stuck inside you, official limits are not bad ones to keep to - even if you had a good run before. 4 is pushing it but certainly safer and more likely to be successful, than 7. (Notwithstanding previous experience!)
For more info on the Cleo here's the faq at the website:
FAQ about Cleo 90 Infusion Sets