Sometimes even the best developers can have unforseen issues with their products that they create. If, I purchased from this vendor before, and they provided good services for when their products did not function properly then , yes I would most certainly give them another chance.
However, I have learned the hard way to start doing my research before I make that intial purchase when it comes to a vendor I have not done business with before, just to see if there are already issues like the ones you mentioned in your question topic here.
Furthermore, even if I have done purchases with a vendor, I always make certain that there is a option to get a refund if the product does not perform like it should, and if they are using outdated products I typically will research the product name to see when it was last updated etc.
by doing some of these steps that I mentioned it has thus saved me a lot of trouble, and time and helped with more helpful tools that I will not have to take weeks to correct bad coding etc.
Hope my answer helps some with your question topic