SAA -Damage to baggage and their unhelpful tactics

I decided it worthwhile to purchase a new bag for 3 planned trips to the USA. After my 2nd trip (2nd time I used the bag), the back bag of the bag was torn and cracked (as if pierced) and the side was halfway **********. I was shocked, however felt comfort in thinking that the SAA will provide a new bag since SAA ruined this bag. SAA decided to fix my bag instead. I agreed to this, even though it would be effort from my side (one has to take the bag to SAA and fetch it afterwards (no deliveries)). After my 3rd trip I noticed that the side stitching (which SAA fixed) was a few centimetres short. This creates a weak spot where the bag will surely begin to tear again