Class 'PragmaRX\Tracker\Vendor\Laravel\ServiceProvider' not found

I had installed PragmaRx\Tracker package several months ago to my project. I started to deleting the package from laravel project through following steps:

1. composer remove vendor/PragmaRx/Tracker
2. remove package name form composer.json file
3. removing package from provider and aliases list in config/app.php file
4. composer dump-autoload
5. composer update
6. also php artisan dump-autoload

I also tried a bunch of other ways to remove the package.

after removing the package I'm getting this error when I run any artisan command (even "php artisan serve" command):

In ProviderRepository.php line 208:
      Class 'PragmaRX\Tracker\Vendor\Laravel\ServiceProvider' not found

It's obvious that the package and its related files have been removed! but I couldn't find out the error's reason.

my laravel version is 5.5.4 .

any idea?

via Chebli Mohamed