Child Record from a ref column are not associated

[Espegg]

I have two tables:
TABLE 1
-Deal ID
-Product
-Amount

TABLE 2
-Payment ID
-Payment name
-Deal ID
-Payment Amount

I have done for Deal ID a ref column in TABLE 2 based on TABLE 1, the problem is that if I try to create another Payment record from an exiting Deal ID, the payment record created is not associated to that Deal ID.

Why?