Newbie needs help dealing with combo problems
So I say newbie because I am new, but I'd like to think I'm fairly competent at this game (though it's looking like I won't quite succeed on my first loop--I'm 2 days away from the very last payment and I only have 150k and mediocre assets). What I need help with is the one lady with purple hair who offers to sell me unusual items at outrageous prices. I made the mistake of "unlocking her as a customer" so to speak without knowing the problem it would cause, and now she keeps auto-ending my combos by trying to sell me stuff at outrageous prices and then immediately refusing and leaving when I counter-offer with a sensible one (even up to 100% of the normal price).
Is there a way for me to get her to stop trying to sell me stuff, to make her sell stuff to me at reasonable prices, or if worse comes to worst, somehow manage to make a profit off of buying something of hers at the outrageous prices she offers (if I even can muster enough to afford to pay enough to satisfy her)? All I know is she's ruining my combos left and right and I cba to repeatedly save scum each time I open my shop just to make sure she doesn't enter and run the risk of letting her auto-kill my combo(s).
I'd check the wiki, but I don't remember her name and I haven't beaten the game yet, so I want to avoid spoilers if I can. (Thanks in advance!)