Why is my Apple Pay double click option greyed out?

Let’s revisit AssistiveTouch. You might have missed something. Please follow this path,

iPhone > Settings > Accessibility > AssistiveTouch — disable, if it is disabled, momentarily enable and then disable again. 

Scroll down to bottom of AssistiveTouch screen > Confirm with AssistiveTouch > disable

After confirming above, please do a forced restart following the instructions in the Apple Support article linked below. If you’re unfamiliar with the procedure, follow the step by step instructions in the article. 

Force restart iPhone - Apple Support

Here is what Apple says;

”Reset All Settings: All settings—including network settings, the keyboard dictionary, location settings, privacy settings, and Apple Pay cards—are removed or reset to their defaults. No data or media are deleted.“

Reset iPhone settings to their defaults - Apple Support

No passwords are deleted except WiFi and/or network passwords. Your cards will be removed from your Wallet app and will need to be added again.

The only thing left is reset all settings. This sets all iPhone settings back to factory defaults. It does not change settings within third party apps.

Please follow this path,

iPhone > Settings > General > scroll down > Transfer or Reset iPhone > Reset > Reset All Settings

Have you changed any settings in Accessibility in your iPhone Settings app?

What model iPhone and version of iOS are you using?

Do you have any Focus modes set? Do you have any Screen Time limits set?

Is your iPhone a managed device or are you part of an Apple Family Sharing group?

I’m out of ideas. Please contact Apple Support.

Egypt

0800 000 0888

Choose your country or region - Official Apple Support

Are you the organizer of the Apple Family Sharing group?

The organizer has changed settings affecting your account/iphone. They have limited/restricted your Wallet.