I got the error response:
Does this mean that we should not be sending the zip field?
If you want to send any parameters for requests with specified token you could change configuration settings.
Go to Data Vault > Administration > Configuration Settings and check "Allow to override Billing information for tokenized payments" setting in the "Billing Info" section:
Data from the tokenized API request (e.g. zip field) will override Data Vault client's billing information.
If "Allow to override Billing information for tokenized payments" setting is not checked, parameters can be present only if no token is specified.