#Abraham also complained to Abimelech

Possible meanings are 1) Abraham was complaining about what happened or 2) "Abraham also rebuked Abimelech"

#concerning a well of water that Abimelech's servants had seized from him

"because Abimelech's servants had taken one of Abraham's wells"

#seized from him

"taken from Abraham" or "had taken control of" (UDB)

#I have not heard of it until today

This can be stated in positive form. AT: "This is the first time I have heard about it"

#Abraham took sheep and oxen and gave them to Abimelech

This is a sign of friendship and that Abraham agrees to make covenant with Abimelech. (See: [[:en:ta:vol2:translate:translate_symaction]])