Exodus 5:22-23
“Moses returned to the Lord and said, “Why, Lord, why have you brought trouble on this people? Is this why you sent me? Ever since I went to Pharaoh to speak in your name, he has brought trouble on this people, and you have not rescued your people at all.”
Prayer is a conversation and never forget to be real, to get raw. Trust me - God can handle it - including your complaining. That’s all that Moses is doing here - complaining because God hasn’t lived up to his promise (yet). God was building character into the life of Moses.
Man I would have run away at that point but Moses had faith and stuck it out. God came through because he said he would.