Do you have a class named Account? If yes, I would suggest you to rename it to something else. Naming a class with any of the already existing class names(or objects) is a bad practice and will always lead to confusion and errors.
Do you have a class named Contact? If yes, I would suggest you to rename it to something else. Naming a class with any of the already existing class names(or objects) is a bad practice and will always lead to confusion and errors.