But i use Bitcoin wallet app. As wallet. (bitcoin . org)
I used economy so it is a terrible low fee, didnt know that.
Two wallets that I know from bitcoin.org have economic fee options Mycelium and Schildbach Bitcoin wallet.
Mycelium has RBF I guess so the wallet app you talking about is the Schildbach wallet.
So I think you sent BTC from your wallet to a website to pay for something(services or products)?
And then their payment gateway/page has expiration am I right?
If I'm right then you won't be able to make a CPFP because only the receiver can do that.
Do you mind telling us what website you sent the BTC to? You may need to contact the owner because they are the only ones who can do CPFP. So try to contact them and just tell them your current transaction issue and talk about for extra fee later if they ask.