It can be tough to move a royal into a new enclosure type. The breeder was likely keeping her in a confined space where she felt more secure. She's now basically feeling exposed with this giant human thing harassing her with mouse carcasses nonstop. You've tried at least 3 different feeding methods(leaving, braining, relocating) in the 2 weeks since you got the girl. It's a good idea to let them settle in a week or two before offering the first meal. If it's denied, wait a week before the next offering, etc. You'll have better luck if you can get some live prey but I wouldn't cross out f/t yet either if that's your goal - or only option right now. Probably the most common mistake when offering f/t is not heating it up enough. You want to heat up right to around 100 degrees fahrenheit. The next mistake is being to aggressive with the offering. Use your tweezers, tongs, chopsticks, whathaveyou and offer the thoroughly warmed rodent starting just out of striking range and doing a little "zombie dance" to just within range. Don't get close enough that the rodent(including hairs/whiskers) touches the snake as that can turn a curiously hungry, though possibly shy, royal into a scared critter who now wants nothing more than to escape.