I have used WebDoctor for medical certificates numerous times over approximately the last couple of years.
I chose them because they had positive reviews and were a little cheaper than the rest. They have been excellent, very quick, very professional, each and every time.
On my most recent usage there was a glitch which led to me making a second application and payment (my fault I should have contacted them first). The WebDoctor Team spotted two applications and payments and refunded me before I even contacted them. That is honesty folks!
I don’t know why all the negative reviews - perhaps competitors trying to steer traffic their way - but I do highly recommend Web Doctor as prompt, honest, professional and reliable.