Thanks for reaching out!
What issues are you facing with the bootable pendrive ? What error you get during booting ?
Please refer here for help : https://learn.redhat.com/t5/Certification-Resources/Getting-Ready-for-your-Red-Hat-Remote-Exam/ba-p/... or this exam preparation ebook here: https://www.redhat.com/en/resources/remote-exams-preparation-ebook and see if it resolves your issue.
Otherwise, Please contact our exam support team here : https://rhtapps.redhat.com/comments