Facebook Chatbot for Smartphone Sales

I'm looking to build a chatbot for leads coming from my Facebook Marketplace ads.

Here’s what I need the bot to do:

1-The user is trying to sell their phone and wants a price.

2-The bot should ask a series of structured questions (no free-text answers, only multiple-choice options) to collect the device details—exactly like the form on the external site.

3-After collecting this info, the bot should automatically send the data to an external website to get a price estimate.

4-The bot should take the website’s estimate and add 15% on top.
The bot should show this adjusted offer to the user.

5-If the user accepts, the bot will share contact details for one of our local agents so they can coordinate a safe meet-up for inspection and payment.

Reference website for the questions and flow:
https://www.ecoatm.com/pages/sell

I do not have any API, so you need to built it.

Platform I'm currently using: ManyChat but I am open to any platform that you can suggest.

Let me know if you can build this and send me your offer.
Thank you