More to the point, what is so special about these Wurth screws that means they can't be sourced else-where, not seen anything in the Wurth catalogue that appears especially unique.
If these screws really are unique to Wurth, try phoning them again, Wurth seem to be very much a 'rep' orientated company, could be that they were between 'reps' for your area/range and thus no visit!
Just to show how stupid their admin processes are, I once needed some items that were in another range from those that our area rep dealt with and although he could look the part up, tell me a price, tell me availability etc. he could UNDER NO CIRCUMSTANCES (his emphasis) place an order for them, he could though ask the area Rep for that range to call but that would require a second account to be opened should we place an order! Needless to say we managed to get what we wanted elsewhere...