Hmm, Do you have Caller ID, so you can see when she is calling and just get DSD to answer it, or not answer it at all ??

Or my other suggestion... (my very childish - but my way to keep the peace) just be fake, don't go out of your way to help her, give her the common courtesy you would any stranger "hi hello, hows are you? here is DSD" nothing more...

Does that sound weird...

Just bang your head against the wall once shes off the phone...

Sorry I am not much help!