Nitro without a payment method or adding applying a nitro credit into nitro

I have a bug on my account right now, which sadly support team hasnt been much help in solving it but, a nitro credit isnt working on my account right now. I had a subscription last month but now its not applying. I tried using contacting support but they werent much help. I personally would love if you forcibly apply a nitro credit if your nitro has run out and doesnt not apply automatically, or in my case, is bugged.