Nasal pillows aren't recommended for slotted nares, but that doesn't mean they don't work at all. Usually it just requires moving up to the larger size to get full coverage of the nares. What often occurs with slotted nares is the need to sit the pillows up tighter agaisnt the nostrils to stop leaks. This lead to irritation. softer pillows like with the Aura and CL2 seem to stop this for some folks.
Try the larger Swift pillows before you retire it for good. I have slotted nares and find the new Hybrid works well for me. Softer pillows and the air doesn't go directly up your nose so it isn't as stinging as it iw with other mask.