There are a few issues with the sentence.
First, I would recommend using "receive" instead of "record," as a Ouija board does not create a recording.
The main issue with the sentence is "supposedly." That word implies uncertainly about the verb or adjective that it is modifying. In this sentence, there is not doubt that the spiritualists used the Ouija board, but rather that there is doubt whether the Ouija board transmits or receives. To use "supposedly" in this context, the sentence could read:
Spiritualists supposedly transmit and receive messages from those no longer alive using a Ouija board.