To give with one hand and take with the other
Literally 'to give one of lime and one of sand'. Describes alternating praise and criticism, or alternating good and bad treatment.
He always gives with one hand and takes with the other: he praises you and then criticises you.
—What's it like working with her? —She gives with one hand and takes with the other.
In that agreement they gave with one hand and took with the other.