Thank you for that information. So she basically learned from the beginning that something she wants may be taken from her without giving an actual command that will allow her to know something better is coming. From there you tried to bribe with treats, but the problem was already formed.
I would pick up all toys, and start again with something that is not very exciting to her. this could be car keys, a whisk from the kitchen, something that she will retrieve but won't mid giving up for something better.
I would do clicker training with her so when she gives up the item you click that behavior which marks it, then give the reward. After a week of this, I would start implementing the cue give.
Eventually you can toss something , say get it, bring give, and she should be able to follow those cues.
What happens when we just take something from them is we take away some of their free will, this they remember, so we want them to know it is their free will to give something up in a trade up for praise and something better. You may have to use liver as a treat, something she has not had before so the ante is upped.
In case you are not familiar with clicker training I will put some links below.
Clicker training/positive method training/ print off
video’s to see how clicker training is done,(go to videos )