my two pennyworth is use the credit card company to exert.pressure. jomashop need that, and credit card providers share liability potentially. mention particularly all the assurances they give, particularly on the website where the weasel words may have been left out.
Also depending on where the sale took place, the warranty cannot have the effect of reducing your consumer rights, which are normally broadly that it conforms to description and is of satisfactory quality. If something was put in the description, about the crown being heavily worn or condition being in need of a service then maybe not.
I’ve only made one “decent” size purchase on joma but a bunch of seikos and such. They had one second hand watch I was looking at but it went quick. I think they have a pretty good reputation there are always some risks you gotta eat with going grey but life is full of risk.