Most second-hand cellphones retailers will use the term "Refurbished" to describe their devices. In fact, they only clean, test and pack the phones for retail. There is no refurbishing involved.
Notwithstanding the warranty they are offering, there's no difference between their phones and a random phone bought on Kijiji/Marketplace.
At Celeri.ca, we are committed to transparence towards our customers. Our phones are truly refurbished. Each device has been opened, inspected and cleaned inside, repaired if needed and sealed-back using new original seals. It allows us to detect non-visible damage such as liquid penetration or aftermarket parts. This whole process increases the overall quality of the phones we are selling. And it works well; we rarely need to process a warranty claim.