If the money thing comes up again, you might say, with only the tiniest bit of hurt in your voice, "I'm a little insulted that you would think your lack of money to spend on my girls is going to ruin the visit for them. I didn't raise greedy children. They love you for yourself, and I'm hurt that you would be so insistent that they don't."
And then hang up.
Go on the offensive a little bit, and point out exactly how offensive these objections are. Because, well, they are.
We've all skirted around that, but it's true.
And sometimes when people cling to some point of view like this, a brief attack (taking the offensive position, instead of the defensive position) will jar them long enough for them to see someone else's point of view.