Thanks for C-W-S’s introduction which is extremely useful. Last year I raised a question here and he immediately provided great advice. Here I come back to follow up the event. Short story: May 28th, 2017 when I arrived in LHR, my connecting flight to OSL had been cancelled twice. BA finally rebooked me to DUS on the next day. However, my luggage was received in 3 days! In June, I online claimed flight cancellation and luggage delay compensation. In July, 250 Euros for cancellation was approved. In Nov, BA fully covered my claim for 3-days luggage delay, which was 1059.78 Euros. To be honest, this was quite generous but it took too long to get BA’s response.