Iam not a member of a credit union, therefore i use any of its services.
can't.
have to show id to.
have to pay to.
can.

i am not a member of a credit union, therefore i can't use any of its services.

Explanation:

Credit union is a financial institution formed by the association of persons to provide financial services exclusively to its members. Members are both owners and users of the cooperative, participating in its management and enjoying its products and services. Therefore anyone who is not a member of the credit union cannot use any of their services.

For this reason, we can conclude that the correct sentence is:  "i am not a member of a credit union, therefore i can't use any of its services. "

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