Acceptance & Consideration

Dear Sir,

In Acceptance , it is said in case of Household Fire Insurance Co v Grant

that Postal rule applies (shares case)

and outcome was “posting acceptance creates a ‘meeting of minds’, which created a binding contract”

but defendant never paid for shares which he was allotted by letter.

and in consideration it says

“Consideration is a two-way thing in simple/parol contracts”

so if defendant did not pay for shares , the transaction was not completed hence contract was not complete due consideration being one way only.

please clarify if i am mixing up two different things.

Thanks