Most people that work with pay per click are going to give up. Chances are you will be one of them.
You signed a one year contract with an agency to provide you a bundle of clicks for a set price. Your risk is zero. If they don't produce the promised number of clicks, they will extend the contract free of charge.
Your agency priced your contract by examining a basket of keywords. The basket includes good keywords and poor keywords; ones that convert to leads and ones that do not. Your price is 2X the cost of the keyword basket. The agency will make sure to only bid on cheaper keywords in order to keep their cost low and not exceed their cost target. If they are unable to get enough clicks within the budget they will extend your contract, providing clicks beyond the contract term for free. They have a guaranteed margin. You take all the risk.
You work with an agency that charges you a percentage of your ad spend to manage your ppc. The more you spend the more they make. You give your agency a budget and a target cost per click. They work to stay inside it.
The agency has incentives to get you the most expensive clicks possible that still stay inside your cost per click budget. These will likely be some of the best converting keywords available. Keywords that cost less but work equally well will be missed. Your click volume will be less than it could have been and you will be pressured to increase your spend.
The work your agency is doing doesn't change with ad spend (mostly). When you increase your budget, your agency earns more. Most of the increase goes straight to the agency's bottom line.
Your agency is a big company that is a Google Certified Partner. This seems like a safe bet and an easy choice.
Large agencies work on volume. They have dedicated sales people working from a call center. The sales people are trained to close a deal. They typically promise anything to get you to sign.
The agency has dedicated account managers to keep you happy and sell more services. After signing you are moved to an account manager knows nothing of what you were promised. The account manager has only a surface level knowledge of pay per click management. They work with the technical department.
The technical department is where you will find one or two Google Certified people. Their role is to keep their automated systems running and look into customer complaints. In these companies, nobody is managing your campaign.
You run your own ppc campaign. You use tools like Google Express to easily build and deploy ads.
PPC requires constant attention to make it work well over time. There is a reason why ppc management platforms have a lot of settings and controls. Set it and forget it results in poor performance. DIY works if you are willing to become a ppc expert and spend several hours per month managing your campaign. Small companies will find better return on investment in other areas of their business.