Hm I wonder if you take Shayla outside and turn away and when she squats turn right back and when she is done give her a treat... She might be shy. When Maxi was little I couldnt hold the giggle when he would go poo on the pad as he was making funny face. So he got all shy
After that he would just sneak out and go on the pad when I was not looking. They are such a smarty pants.
After he got potty trained to go outside he was fine though.
Choke chain?
I am glad to hear you didnt hire that trainer.