Anyone can make a mistake. What matters to me is how they respond.
DigiKey sent me the wrong part once. Instead of 20 transistors, they shipped 20 MC74HC541AN buffers. 18 of them were packed in one long strip, so they had to use a much larger box just to accommodate it. I called them, and they checked the cost to see if they wanted them returned--nope. They asked if I wanted the right parts shipped overnight--they'd pay. Didn't need that, so just requested ground.
I don't expect anyone to be as good as DigiKey with things like this. I know if I need parts in a hurry, I can order from DigiKey and a few others, request overnight delivery, and have the part or an email or phone call within 2 days. If I can wait, there are more options. It's definitely something I think about before deciding who to order from. With many companies, it typically takes 5-7 days to get parts, depending on shipping. Some take 2-3 days to pack & ship the order. I never place a first order with an unknown supplier when I need something quick. I get to know them, and then pick who to order from based on a bunch of things, including time to get the parts.
If a company didn't even let me know there would be a delay, and then it took 3 weeks to get the part, that gets factored in. As long as they actually deliver and handle any mistakes decently. Looks like these guys have 3 strikes already. Slow, didn't let you know, sent the wrong box. sigh!
By the way, if anyone needs some of those buffers...