TMSII Application Related Issues: Contact MIC Support: Phone: +1 313-263-4912
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For urgent issues, please call the phone number listed.
Missing Data and Country Communications Issues: Contact GM IT: Phone: +1 313-667-3264
TaxIT@gm.comPlease Note: Emails are monitored 7:30 AM - 4:30 PM ET Monday - Friday.
For urgent issues outside these hours, or on GM holidays, please call the phone number listed.