Do you have a recomended service? Part of our service has us hosting a form for our customers that is exposed to their users, so accessibility is a priority.
I've worked with people from Level Access[1] and Deque[2], there is also TPG[3]. I'm not sure how much money they cost, but they are the real experts in the industry. Some people on Fivver offer services, but I don't know how qualified they are.
[1] https://www.levelaccess.com/ [2] https://www.deque.com/ [3] https://www.paciellogroup.com/