Awful experience with Saudi Airlines. Best way to get my compensation and rights?

I am not trying to rant here but I just need to briefly tell my story:

Booked a flight from Frankfurt to Jakarta together with my wife, for departure 23th of June and return on 4th of July. Our standard baggage allowance was 2x23Kg for each of us, and since I haven’t come home for a long time I decided to bought an extra baggage to carry my chocolate gifts for my family. Here are the list of problems we had:

• On 20th of June, I was just checking my booking on their website and suddenly I received a pop up saying that I had to approve new schedule for my return flight, it was moved from 4th of July to the 6th July. No prior emails whatsover. I was shocked and furious because I had important meeting on the 6th of July so I called their customer service right away. They told me they would look for other flights. After almost an hour of waiting they told me they couldn’t find any. I just accepted my defeat and informed my company right away that I couldn’t attend the meeting.

• On 23th of June, when we arrived at the Frankfurt airport, to another shock we saw in the airport timetables that our flight was CANCELED. Again with NO emails from Saudi to inform this. Then I waited for like 4 hours in a queue in front of their counter to get my replacement flight. The ticketing staff told me that there was a flight the next day with different airline (Qatar Airways) but that means I had to give up my baggage allowance PLUS my extra baggage that I bought. Other alternative was to take the next flight from Saudi but it was on 25th of June and they would provide the hotels and the meals for the duration until the next flight. I took this alternative since I didn’t want to lose my baggage allowance and Qatar Airways baggage allowance was only 25kg per passenger, so the baggage allowance different was pretty big.

• While I was waiting for more info of our hotel and meal allowance with the other affected passengers, a manager from Saudi Airlines approached me (he seemed angry) and asked me why I didn’t take the next day flight. I explained the reason regarding my extra baggage that I bought. The next sentence that came out from his mouth still made me furious to this day: “Just pay the difference of your baggage, I don’t want to pay for your hotel and meal for 2 days”. He then escorted me back to the ticketing counter and demanded the ticketing staff to put me in the next day flight with Qatar Airways. The ticketing staff then explained to him that I had problem with my baggage allowance and the next day flight was already full anyway. Then the manager told me to pay the second night myself. After some heated arguments between me and him, another Saudi staff lady told me just go to the hotel they provided, while she tried to explain the situation again to her manager in Arabic.

That’s not the end of the story, the final blow to us was when we reached our hotel. The receptionist told us that the Saudi manager HAS NOT PAID the room for us, but he did for other passengers who were staying for a night. My wife literally broke crying out of anger. The receptionist tried to call Saudi Airlines again but they were not unreachable because it was already late at night. After waiting some time the receptionist told us that there was another couple who still hadn’t showed up so we could take their room for the night. Finally we spent the night there and the receptionist called them again in the morning and finally they did pay for us.

Again sorry for the long story and rant, but I just want to know the best way to get my compensation of the both delayed flights and no information in any form whatsover regarding the delays. And also especially how can I report the manager since his treatment to us was really unacceptable since we were the ones at disadvantage but he demanded us to pay extra for the inconvenience they caused. I was thinking to fill the complaints form but not sure if this is the best way.