0 credits on Qwiklabs account even after having $300 credits on my account

[UdayMahajan]

I've taken the "Cloud Developer" learning path. There's a lab which requires $5 worth of credits to be accessed. So I availed free credits worth $300 for three months by creating an account. But it still shows 0 credits inside my Qwiklabs (Google Cloud Skills Boost) account. 
If there's a way to access those $300 to take the lab, please let me know. If there's no way to access the lab without purchasing the credits, please suggest a way to get temporary credits. 

Thanks.