Build an Online Store

I have a storefront already built on my customer's behalf and I need the checkout process reviewed. The customer is experiencing a significant number of abandoned carts and customers are having difficulty with checkout. I have done test checkouts and I, myself, am not having problems checking out. Payment processors include [login to view URL], Paypal and a phone order option upon checkout. Another issue is order notification is not being received by email and orders are sometime not posting in the back office. i.e. a customer made a purchase recently and [login to view URL] processed the order but the order was found in abandoned cart area vs. showing up under orders in the back office. JOB REQUIREMENTS 1. thorough review of the storefront's checkout process 2. identification/list of recommendations/steps necessary to provide resolution of checkout problems. A price quote is desired for steps 1 and 2. 3. recommendations regarding reducing abandoned carts. List of steps necessary leading to recommendations and a price quote based on recommendations.