I'm really sorry but I felt compelled to make a post here because Mulberry seem to be having some very unfair ranting by lots of people pointed in their direction when it isn't really warranted.
It seems like they have offered to replace the bag for you - so I'm sure you will be able to just get a replacement Lily. As an early poster mentioned, she had the same email and was given a UJ Bays in lieu of an old Mabel, so surely this is an indication of amazing customer service? Certainly, I don't know of any other brand that would do this?
Next up - the tarnishing of the chain strap. Maybe it's just me, but I have various metal objects - both around the house and jewellery - in time, they tarnish. That's just what happens - nothing to do with Mulberry's quality. I have an 18ct white gold ring - after been worn for a while - it tarnishes - it needs to have it's rhodium plating replaced. That's just the nature of the metal. The fact that they are holding their hands up and taking responsibility is fantastic. To offer a replacement for a 2 year old bag is even better.
At the moment, it seems that their email might be slightly vague, but I think it's really unfair that everyone is reading in to it the most negative way possible. Perhaps it should be clarified first before everyone assumes the worse?
CP - please don't take this personally, my comments are just made in general in the direction of everyone who seems appalled and is encouraging you to rant at Mulberry. I honestly think that their customer service is fantastic (I've had issues myself in the past and it's been dealt with very well indeed) especially compared to other brands. I hope that you manage to get the new Lily you are hoping for.