Thank you for your question. U.S. contributor here. I am a licensed attorney and happy to help.
There's no 30 day cooling off period on a contract, no. There are several federal laws in the United States (known as "cooling-off rules") that allow you to cancel certain contracts within a few days of signing them. They apply to contracts made during door-to-door or trade show sales, contracts for home equity loans, or delayed mail order or Internet purchases. In addition, some states' laws allow you to cancel contracts for health club memberships, dating services, and weight loss programs. Other contracts, such as to purchase a vehicle, typically cannot be cancelled, unless the contract itself has a cancellation period written into it. So, you'd want to read the terms of the agreement to see whether you can cancel.
Alternatively, if you were mislead into signing the contract or there was detrimental reliance that caused you to enter into the contract, it may be possible to cancel the contract (though it could end up in court). For example, if you were guaranteed a week vacation in a 5 star resort, and were actually sold a stay in a run down motel, then the contract is arguably void for breach of contract, detrimental reliance on the false promise and misrepresentation.
If you paid for this with a credit card, you can try to dispute the matter with the card company also. They will reverse the charge temporarily while they investigate the matter and should they find in your favor then you wouldn't be responsible to pay.
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