Summary: If you buy a product and it has no defects then it's fine - if it has issues though their customer service is very dodgy.
Bought a galaxy S8 in 2018 (new, NOT refurbished on website), but the box was already opened. When I asked about this they said it was for quality checking purposes which made me suspicious since I'd also bought my mother a S8+ a month earlier from Einfo which was unopened. Foolishly, I still bought the S8.
After almost a year I had an issue where battery drained very fast after reaching ~25%. Got battery "replaced" under warranty (gave them my phone for a week), but after getting my phone back I had the same issue. At this point I couldn't trust them any longer so I went to another phone repair store who promptly replaced the battery right in front of me at a cost, and the issue has since been solved.
When they opened up my phone, they said they were certain both the battery and the phone itself was not new. The battery looked worn down with dents everywhere, and the phone back cover itself had a lot of pasty glue which would only be there if it was refurbished. It's not nice having paid "new" prices for a refurbished phone.
Einfo may be cheap yes, but you take a gamble when buying from them.