I don't know which doula service you used, or what the terms of your contract with them was, but a professional doula package would normally include much more than just the birth support itself - for example, antenatal visits with you and partner, help with putting together your birth plan, comprehensive birth notes, information and support during pregnancy and especially during the on call period, then there is usually postnatal support including help with breastfeeding. Some doula packages also include antenatal classes. 1000 seems quite high if none of that is included but I am surprised that all of this wasn't clarified before the birth. A professional doula would go through all the arrangements, including the fee, beforehand, and there should usually be a contract outlining all of this including things like what happens if you have a cesarean. As the previous poster said, you wouldn't expect a doula who spent a long time with you to charge you more so it does seem a little harsh to want to deduct money from her fee because you had a quick labour.
To the poster above who asked if the ob gyn was not going to be helpful at their birth - well most ob gyns only spend a very short time with their clients when they are in labour, most only come in for the very last part of the pushing stage - can be as little as 15 minutes !
To the person who asked why hire a doula - doulas provide continuous support during birth - usually beginning in the earlier stages of labour when you are still at home, and then in the hospital until the baby is born. Unlike the nurses who will be changing shifts and have many different clients to look after, a doula will be focused on you alone. Unlike in the UK or Australia there is no midwifery care here, so it the Dr. who will come in for the delivery - the nurses are basically there just to provide clinical care such as taking your bloodpressure - they don't have the time or even the skills to help with things like going through your options for pain relief etc. And in the event that things don't go exactly according to plan a doula can help by providing information and helping you work through all your choices, something the ob gyn may not have the time or inclination to do.
Incientally, most doulas only take a few clients at a time to avoid "clashes" happening but it can happen as babies can be born early, late, or whenever. But most doulas would have a back-up arrangement in place so that if you call them and they are at another birth you will still be able to get support. If you are thinking of hiring a doula this is definitely something to ask about.