Yeah I'm feeling a little confused by this. The head's up, "I'm in labor" call was very nice. It's a lot easier to rearrange your day when you have one of those, and as a doula, I appreciate it. But I'm confused by the 'two and a half hours' notice. If you called your doula at 11:15 and asked her to come, then I would expect her to be there by 12:15 under your circumstances (small town, easy drive, etc). While nice, It doesn't matter if you gave her a heads up beforehand, you can't start the clock before you've actually said yes I want you to come. However, I would say from the time you said 'come' to the time she gets there, one hour is reasonable, even if she did say 30 minutes, that's faster than most doulas I've talked with.
Now... either way, 50% of the money back still puts the blame "on you" (as opposed to her I mean, for not getting there soon enough). So for arguments sake, we'll assume that you called her at 11:15 and said "Ok, I want you come now", she got there within an hour, but it was still too late for the birth. Not her fault. But even with it not being her fault, from what you're saying, her contract very clearly states under those circumstances that you should receive 50% refund. You're essentially saying, "This was our mistake, we should have called you earlier, so we're taking the hit", since the alternative (her not getting there in time by her own mistake) would have her refunding the whole amount.
That really should be the end of it. You signed a contact with her that stated two options for a missed birth- 50% refund, or 100% refund. That was her choice to include those options in the contract, and you both signed it. End of story. I've seen several doulas that state in their contract that if they miss the birth due to no fault of their own, that they owe you no refund, but this doesn't seem to be what her contract says, and since it is a legal binding document, she has no grounds to go back on it. Period. The only question is whether the missed birth was 'your' or 'her' fault, but either way, you and DH should receive at least 50% of your fee back.
I would definately sit down with her, or if you're not comfortable, send her an email, and show/send a copy of the contract with the relevant part highlighted, and just say "Hey, I'm a little confused here, DH and I are willing to admit (if you are) that we should have called you sooner, so I know that's our fault, but the contract here says that if that happens, we still get 50% back. Can you tell me why that's not happening?" And it sounds harsh, but if you need to, then remind her that as a self employed/small business owner (how it is here in canada anyways with a doula business), she is legally obligated to stand by the contract she signed with you. You legally have every right to take her to court over it (though I'm sure it won't go to that obviously, a signed contract really isn't something to be taken lightly)
