Bless her heart. There is a lot going on here.
The mother problem is obvious. She is feeling fear, hurt feelings, guilt, confusion.. She is under a lot of stress.
She is not "being bad" she is having a reaction to all that is going on in her life. Imagine what a teen would feel like with all of this going on around them? These emotions are very hard to deal with.. Now think about it, this is only a 4 year old child.
None of this is on purpose. This is a manifestation of her stress. It is like a reaction. The more you push her, is still pressure from you. Instead know that she is not realizing what is going on. She is distracted.
Yes, you can remind her over and over, but she wants to be a big girl and each time you remind her about going to the potty, you are taking that away from her. It is like a little bit of shame.
Instead start modeling the behaviors of going to the potty.
You will feel strange at first, but it will show her that even the grown ups need to remember to go and not wait until the last minute.
"Gee, I just drank a big glass of water I better go t the potty before I get in the car. "
"Dad do you need to go to the potty before you leave for work?"
"Before I put on my coat, I am going to try one more time to go potty, I do not want to have an accident." "We are not going to be able to stop for a potty break for 2 hours. "
And then praise, praise, praise, praise her for going in a timely manner. She does not need a reward, just your approval.
At the end of the night if she did not have an accident, mention it. "Wow, you did not have any potty accidents! High five!"
If she did have an accident have her change herself and clean herself up. Then just say, "I know you wanted to to remember about going to the potty, maybe tomorrow you will be able to remember."
When I was this age, there was lots of turmoil in our home.. I used to also have accidents. I did not want to interrupt the fun I was having, because I knew when I went home things would be stressful and I would not get as much playtime.. It really does have an impact. It helped when my mom made a big deal when I made it through the whole day. She purchase super pretty panties for me as a reward on those days.
Just hang in there. She is really in transition and the stress from her former life will never totally leave until she is old enough to really understand what went on.
Just stay as supportive and as empathetic as possible.