I cant upgrade my Icloud storage. It keep saying 'Your payment method was declined' And asks me to update payment method and then it keeps going round in circles

Do you have a VPN app or VPN based app blocker installed? IF so remove all traces of it including from Settings, General, VPN &...

Have you changed the iphone's country or is it different from the country of your bank? Set it back.

If your account is suspended or blocked you must reach out to Apple Support directly. Depending on your region, you may be able to reach them here: contact Apple Support 

Here is additional information from Apple if your payment method is declined.

If your payment method is declined in the App Store or iTunes Store - Apple Support

Reasons your payment card may be declined

1. Account suspended for suspected fraud.

2. Address in your iTunes account does not match exactly the billing address for the card

3. Error in credit card number

4. Insufficient balance or you still owe money on a subscription

5. The card was not issued in the country of the iTunes store

6. Wrong expiration date

7. Wrong security (CVV) code

8. You are connected through a VPN provider that makes iTunes think you live elsewhere - uninstall VPN

If your account is suspended or blocked you must reach out to Apple Support directly. Depending on your region, you may be able to reach them here: contact Apple Support 

No I don’t have one on it it’s really frustrating me now

See my last sentence.

email saying there's a problem with my payment information