Unfortunately, there have been some instances of malicious use of “TeamViewer”. Scammers attempt to sell their services via phone by claiming that your device is infected by malware.
We advise TeamViewer users to be careful with unsolicited phone calls and to not grant access to your devices (e.g. PC or mobile) to anyone you do not know or trust. TeamViewer does not provide remote support services of any kind. Their activities are limited to developing and selling the software tools that providers use to offer remote support services.
Ultimately when they have access to your computer, and probably bank account, then having access to your 2 factor authentication device like your phone they will be able to complete their fraudulent transaction!