Did the Jews listen to Moses or not?
Exodus 6:9 - And Moses spake so unto the children of Israel: but they hearkened not unto Moses for anguish of spirit, and for cruel bondage.
"And the people believed: and when they heard that the LORD had visited the children of Israel, and that he had looked on their affliction, then they bowed their heads and worshipped." vs. "And Moses spake so unto the children of Israel: but they hearkened not unto Moses for anguish of spirit, and for cruel bondage."
How could the children of Israel accept Moses and Reject Moses at the same time?
Both satemets are not referring to the state of Israel at the same period of time. In Ex. 4, they accept Moses under the current circumstances, but in Ex. 6 they temporarily reject him under different circumstances.
This would be like a child obeying his parents on Monday through Friday, but then disobeying his parents on Saturday and obeying them again on Sunday.
You will notice that in Ex. 12:28 they decide to accept Moses again:
"And the children of of Israel went away, and did as the LORD had commanded Moses and Aaron, so did they."