15-day Visa-Free for Cruise: contact for more info

Hi,
I am going on a Royal Caribbean Cruise through Shanghai. My Flight from the UK will land in Shanghai so, my partner and I will be in Shanghai for 72 hours.
Royal Caribbean has arranged visa coverage for over the cruise period.
When the Cruise ends, we will be in Shanghai for a further 21 hours as we wait for our flight home.
I am aware that there I can potentially apply for a visa exemption if it is within 144 hours.
Please can you help me with this as we want to make sure we abide by all regulations and see how to go about applying for an exemption as we should qualify.