If I remember right...on convection settings your food should cook quicker because the fan is circulating the heat. It shouldn't take an extra 40 min for something to cook over the reg time you use to do.
I have the same problem with my cakes cracking. I think that the icing crusts too hard and thus the cracking. Doesn't adding more fat /butter make it greasy tasting? I have my sons wedding cake to ice today and don't want cracking...
seriously...is this a joke? All the cakes I saw in your photos look professional to me. You can charge PRO prices which should start at min of 3.50 per slice or MORE! Your cakes are awesome so keep up the great work and charge accordingly.
I would go over to her house and give her the invoice and ask for the money then. Tell her you have sent email and got no response so you figure her email isn't working. Don't call and leave a message...go over and get your money. Then drop her as your friend.