Just enter it manually.  If it is an expense, + expense.  Use the credit card acct in the entry.

Resolution for 'AMEX download issue: 'I am missing a single transaction on my AMEX download' available: Yes.

The AMEX download issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the AMEX download issue yourself by looking for a resolution described in the article. If it is a complex AMEX download issue or you are unable to solve the issue, you may contact us by clicking here or by using other AMEX download support options.

For more information about resolving issues related to AMEX download in Quickbooks/QBO or to get support for the issue 'I am missing a single transaction on my AMEX download', click the link below: