What happens if i get a refund anticipation loan, and the canada revune service keeps my refund?

In Canada they offer the instant refund, or refund anticipaion loan at our tax offices. My question is how do they know the canada revenue agency isnt holding my refund ? what if they give me a loan based on my tax refund and come to find out, i dont get a refund? I dont need advice on wether or not to get one. But I have a feeling my refund might be held this year.