These things happen on a daily basis and there isn't much you can do, especially on longhaul flights. I filed around 4 times a year for 5 years running about a particular situation that happened every night with multiple similar callsigns. Even today, 4 years since I last filed a report, those flights still operate using their original callsigns.......
I do remember a situation that was filed on very regularly that did get the callsigns changed and began the introduction of alphanumeric callsigns. Every morning Swissair 800, 810, 820, 830, 840, 860, 880 and 890 came in almost perfect formation from various Swiss departure points, over France and into the UK. Around an hour after landing, they all got back airborne and re-formated around 40 miles north of VEULE as Swissair 801, 811, 821, 831, 841, 861, 881 and 891. One summer this occurred 3 mornings in a row and every one was on the frequency at the same time, and each morning at least 2 calls were taken by the wrong aircraft. It took less than a week to get them changed!