honestly?? i think like the previous poster maybe the OP took on a bit too much and not making up a batch of RI for glue (which takes like 2 minutes) and relying on glucose was a bad idea and the last thing you need is decorations falling off. i think Indydebi said it - brides spend months, years even planning their perfect wedding, they dont care about humidity, etc if they show us a picture thats what they expect to get and i dont think its right to blame brides for being bridezillas or have that "well you served it so pay for it" attitude. me, if i was buying a wedding cake i showed a pictured off pinkcakebox to a decorator who said they could do it within my budget, then thats what i would expect to get sitting at my reception. you just have to be honest and for example i have turned down 2 three tier topsy turvey wedding cakes because i dont feel like i could make them as good and stable as the pictures i was shown so therefore i didnt take them on.
i would imagine that most brides are reasonable and arent going to demand a refund for a tiny airbubble or slight mark or something that most cake muggles dont notice but we would, but from the OP's description the cake did sound like a wreck and wasnt an adequate representation of what she was shown so in my book a full refund as the OP has suggested is definitly in order. also, having just been running my business for 10 months, its completely our own fault for underpricing ourselves. if you say you can do something for a certain price that your own fault, if its not worth it, just turn it down or compromise on decorations, etc. i underprices myself completely for my first 3 weddings, completely my own fault but i certainly didnt put in less effort because the brides were getting a really cheap cake. if they show you a picture of how they want their cake and you say yeah you'l do it for $5 then you stil need to make it look like that. so in my opinion the OP is completely right, - full refund and id send a very very apologetic email and possibly cupcakes or a little cake. the wedding cake is like Indydebi said the intrinsic part of the reception and this part of the day was marred by the cake so yeah, a refund and grovelling is in order.
to the OP though, im sorry you had such a bad experience, its really frusttrating