Horrified and ANGRY!!

Thats disgusting Kels, poor Cedes , shes at that age where things like that are a huge blow to her selfconfidence .
You know what i would do ? i would write an anomynous letter to your local paper, complaining about your treatment there, people do it around here all the time
Might not get you compensation or anything ,but heh, you can enjoy saying exactly what you would like to say to them

would be neat to see target do a thing on supermarket and service station toilets.

i remember them doing one on how clean they are but mabye they should do one on letting kids use them as thats just plain rude.

id tell them that you wernt satisfied with their appology and take it further.
id also ask them what they are planning to do to rectify the problem for future kids who need to use the toilet.

That's so shocking Kels - and stupid! I mean, the teenagers who vandalise the toilets probably aren't going to go up to a staff member and ask to be directed to them, are they? So not telling those kids that do ask and need it isn't going to solve the problem anyway, the ones who cause the trouble will know where the toilet is and go in there without anyone seeing if they can help it.

If they're that bothered then they need to take positive measures like locking the toilet and putting up a sign to tell people to get a key from a staff member at the enquiries desk. If that staff member has any doubt about the person using the toilet they can walk with them to unlock it.    Or at the very least ask any kids who ask about the toilet to point out the direction of their parents in the store or something. Surely they can come up with a way to deal with it!

Like you say, it's their problem, not yours, and you are a paying customer who had a horrible experience in their store. It's not just that the girls weren't allowed to use the toilet, but that the staff member they dealt with was horribly rude - that's not on when your girls hadn't done anything, she just made up her mind that they were trouble and treated them as such.

I hope you get better results from higher up the management chain. Definitely put it in writing and maybe even send it to the parent company too - Foodstuffs or Progressive depending on which supermarket it was.