These cups were sold to me as sublimation but were not.
I have been sublimating cups for 4 years and this was the first time experiencing this. I tried baking the image my normal way, then tried with increasing time, each time getting the same result - no ink transfer and what little shadow of ink appeared was easily rubbed off with my finger.
I tried bringing this to the seller. I proved with a video showing their cup vs a true sublimation cup (from another seller) and they still argued that it was sublimation. How can you argue with a video?
I didn't even complain about the quality. Inside the handle was missing paint. Not the quality I expected.
Each interaction with the seller proved they did not care about my satisfaction. I would go as far as to say this seller is a scammer. Buyer beware.