MyProximus planning calendar doesn't work

So I finally get the mail from proximus to go on my proximus and pick up a date when the technician can come to install the internet related stuff. Which I do immediately, given the length of time it took proximus to decide to send it. I click on the link in the mail, get on the website to schedule a day and time for the technician to come over and do his thing. But, surprise; first I notice there aren't any availabile days for the technician; every damn day shown is marked in blue (according to the legend, it means technician not available). Then I notice that from the first page when clicking on "next" it jumps over the second page, rith on the third page. Also there's no possibility to mark any day in the calendar with my availability. So now I ask you, customer service from proximus, are you kidding me? You send me a mail asking me to mark the days and times I am available, and then not allowing me to make any selection? With the experiences I had with proximus until now, it's no wonder why you people have such a bad reputation among clients. Which brings me to another issue, which I intend to pursue by all legal means at my disposal: imposing proximus as the single provider in certain areas of Brussels. It'sforced and plain monopoly on the market and it's breaching the consumer's right to choose other (more reliable and professional) providers. I will be sending on Monday a formal complaint to the national consumers bond to take the necessary actions.
In the meantime, I would like to know how will I be able to select a date for the technician to come over, if your app doesn't allow me to select one? I'm really looking forward to see what your response and reaction will be (if any and if ever) and whether you do care for your clients as you claim, but never showed it practically.