Qatar Airways complaint: 3 months missing luggage

I travelled from Canada to uk ,june 7! ,uk to Doha ,Doha to Tanzania which was my last destination ,when I arrived my last destination ,,which is in Dar es salaam Tanzania,I didn’t find my 4 luggages ,I was shocked they told me I didn’t check i any luggages ,I went lost and found department Swiss port at the airport who’s handling missing luggages ,I filled up the form , and I left to go home with no clothes to change me and my son ,8 days later i received. 1 luggage was june 18!, the sec one I received jiune 20 ,the third one I received july 1 ,was opened and some stuff missing ,i called qatar branch in Tanzania ,they sent me the form to filled up the missing stufff ,I did and sent back to them the same day ,I was waiting my 4 luggage which I didn’t received until now since June 7 up to now ,I called Qatar lost and found department.,they always busy and told me they working on it , now 3 months and a half they still giving me different information here in Tanzania .I spent some money to buy stuff I had in my luggage,I sent receipts to them ,until now no. Refund or compensation .what can I do ,should I sue them or ,this air line is garbage to be honest .