TF...I am so sorry. Stop the guilt...you are such a good mom and have done everything you can for your girls. They need to GROW THE HELL UP. Goodness. Did you notice that you said while you drove off crying she was sitting there reading? Why...she knew you would come back.
I have said this several times on this board and am sure you have heard this but here it is again for what it is worth. I say it because it has made such a huge impact on how I think of things.
You cannot take the pain and consequences away from an addict. They have to experience those things to grow and to way to get rid of addiction. If you continue to always take those things away it robs them of a chance of recovery.
They manipulate you so badly. I am SO SO glad you took the shirt back. Just like the other day...they STOLE your credit card to buy expensive shoes and now want more? Really?? They need to learn the value of work and of a dollar.
TF...I send you gentle hugs. Get off the crazy train and give your girls the chance to grow up.