another
for lexmark
If it can't be set up to do the job it is designed to do, then apart from anything else, you've got a cas under the sales of goods act which says that the product must be "fit for purpose" and "as described". Two phrases that IMHO Lexmark printers are quite incompatible with.
My choice would be a non-lexmark, I would lean towards HP, but many people will say Epson(doesn't really matter, they each have their good and bad points).
I'd also look at if it makes any sense to buy a non-networkable printer and get a standalone print server. That way you've got a cheaper replacement path in the future.