Hi. We are developing extensions for Mautic and can help you. Here is my email karol@thecodeine.com
are you a certified partner? be good if someone here can vouch for you 
No we are not certified but you can check our first contribution into mautic here https://github.com/mautic/mautic/pull/3814. We are also working on the second which will be available to the community in the next week.
If you like to have reference from our client for which we are adding custom extension for Mautic I can provide one 