I had a parcel shipped with a company (not courier itself). Delivery took over 10 days instead of 2 days. During the order below message was displayed.
Parcel delivery within 2 working days throughout. Collection and delivery are not guaranteed but currently enjoy a very high success rate.
Is this legal for them to simply say they can provide the service or not without any responsibility? What's to stop them from simply taking the payment and then simply doing nothing since it's not guaranteed? It seems like gambling to me since it's pure chance that your parcel will even get delivered at all let alone within specified time frame. They also take no responsibility for lost packages regardless of the cause.
This is within the EU so any EU law would apply.