YOU DO NOT assist an animal that knows how to eat that is that simple.
When you buy adults it's a pretty typical issue to have, 50% of the adults I have ever received (loan usually) would take up to a year to resume feeding, they just take a lot longer for some to adjust to their new surrendering.
The first thing I would bet on is the fact that she is a picky eater period 4 years old less than a 1000 grams is a huge red flag when it comes to feeding habit.
The only thing you can do is make sure the husbandry you are providing is optimum even downsize to the bare minimum which usually get them back feeding a little quicker.
Alternative live prey can be an alternative if you are that desperate but I do not recommend it if F/T is the route you want to go well at least not as a first measure.
Here is what I would do if she was mine
Find the smallest tub for it's size (I would get a 15 quarts tub), use coconut chip bedding (such as reptichip), have a hot spot of 88 cool spot of 78 and let the animal settle for a week.
Once a week has pass I would offer a F/T Mouse (not rat) and do it as followed, thaw at room temp near the enclosure, grab the mouse from behind the neck with a pair of feeding tong, warm it up with a hair dryer (make sure it is warm enough) and offer in the tub by moving the mouse around like if it was alive (hence why you need to grab it from behind the neck)
If that does not work I would try again with a live mouse the following week.
And BTW ASF are not what they are cracked up to be mice are actually a lot more enticing to problem feeders.
Reply With Quote