According to the Oxford Law Dictionary “remedy” refers to any of the methods for the enforcement or protection of rights or for obtaining redress for any infringement of such rights. In German Contract Law, those methods are called “Sekundäransprüche” (e.g. the statutory warranty rights (“Gewährleistungsrechte”) or any other rights arising out of any breach of contract).
“Rechtsmittel”, on the other hand, are ways of challenging a court decision (cf. Creifelds Rechtswörterbuch), the English equivalent of which is “appeals”. On that note: the term “Rechtsbehelfe” would be also wrong since Rechtsbehelfe are methods to challenge a decision of a governmental or other authoritative institution. The term is a superordinate term of Rechtsmittel. The German “Rechte”, on the other hand, sets out the rights a party has, including any rights it may have to obtain redress for any infringement.
Our suggested translation for “rights and remedies” then would simply be “Rechte”, or “Rechte bei einer Vertragsverletzung”. If you want to use a doublet, “Rechte und Abhilfen” would be an option.