Linode $100 payment problem

The $38.00 balance on your account will be taken from the promotional credit automatically at the end of the month when payments are collected.

"Is there any chances that linode cut that balance from my credit card?"

This is unlikely as long as your promotional code is still valid. Since the $100 promotional code also has a 60-day expiration period, if the funds expired at the beginning January, then you will be charged. You can see this information in the Promotions panel on the Billing Page of Cloud Manager.