Hello,
I have reviewed your requirement of connecting your existing phonegap app contact us page to facebook messanger and we can easily complete this task with vast capacity of our developers.
Relevant Skills and Experience
We develop native, React native, hybrid, game and AR-VR mobile applications, Below are examples.
https://docs.google.com/spreadsheets/d/1mcXnkbgKyhanqoxnYNFsUqzr1g4Fl9IemTckHK4Zms8/edit#gid=0
Proposed Milestones
$23 USD - Gap filler
What if user don't have an fb messanger installed on his/her cell phone?