Adding new features and improvements to the admin panel and website (Laravel)

We are looking for an experienced developer.

It is important that you comply with the deadlines that you set yourself.

Please do not respond to those who conditionally say that the work will be completed in 2 days, and then stretch the process for a week or more. I understand that difficulties may arise, but then it is better to warn right away, and not pretend that you work for a week, when in fact you have devoted only a few hours.

Briefly what needs to be done:
Add to the admin panel a selection of the payment method that will be used on the site. Integrate the new FreeKassa payment method. Fix a bug when in rare cases after payment, the modal window about successful payment is not displayed.
A detailed technical specification and all details will be provided to the selected contractor. The site is developed by Laravel.