OpenCart - Can't update admin dashboard

I can't update my admin dashboard for some reason. I want to add a feature to search by phone number but no updates are occuring. I'm changing:

• admin/view/template/sale/order_form.twig
• admin/controller/customer/customer.php (autocomplete)
• admin/model/customer/customer.php (getCustomers)

I also tried removing and re-adding cache as well as refreshing in the admin dashboard, and removing the cache manually in /system/storage/cache, to no avail. Can someone help?