I signed and had notorized a contract for release of service with a dollor amount. Now they sent another contract for a lower amount. Allowed?

Your question came in under the heading of Personal Injury, so I'm not quite sure what you are asking.  It appears to be some sort of contract for services of some kind, but you fail to state what kind.  In general, a contract is binding if it has these elements: an offer or agreement to provide a service and an acceptance by the other party. (By setting out the terms and conditions of offer and acceptance, a legally binding contract has been made).  Additionally, there must be consideration and intention.  Consideration is usually the exchange of something, such as wages for work with an employment contract, or a deposit for other types of service contracts.  Each party is basically giving something up or transfering some benefit to the other party.  Intention is where both parties intend to make that contract a legally binding agreement.  If the contract is broken, or breached, then the law can be used to enforce the contract.  If the original contract had the described elements, yes, you should write them a letter and indicate that the original contract is binding and you intend to fulfill your part of the agreement and you expect them to do the same.  If it is a sizable contract, you may want to discuss it with an attorney if they refuse to abide by the agreement.