Mr men and lil Miss and the disaster that followed!

I received an order early in the year from a forum friend of mine. I was so looking forward to being able to make these biscuits for her daughters 2nd birthday.
Mr Men and Lil Miss cookies!
I had planned out how I was going to do them, gave myself plenty of time to do them.

When I had finished them I was very pleased with the end result, but then as the last bits started drying, I started getting a little worried...

See here on Mr Bump, the edges of the outline are starting to bleed in to the white back ground...

I Iced the white back grounds 24 hrs beforehand, I used white icing colour in my icing mix too.
I piped freehand all the characters then let them dry overnight, the next day I out lined them in black edible food colour pen. (This is where I went wrong) I had thought about using black icing, but decided the pen would be easier, quicker....BIG MISTAKE!!

I received a message from the lady the day she received them (She lives in another state from me) the black had completely run and disfigured most of the cookies :(

As you can see, complete disaster...
I refunded her most of her money, they were useless for her to have as party favours, I think it was only fair.
Big lesson learnt for me.