OpenWeb is closed web

I am in need of a new mobile data service provider for a data SIM for my dual SIM phone, and after talking to ChatGPT, decided on OpenWeb, as it seems it is only them and RAIN that offers this. I did my signup on the 5th, and received a link to fill out the debit order. They work through DebiCheck, and they send me a link with a selection of banks on it, saying I must click on my bank's link to complete the authorisation. Only problem was my bank was not on the list. Send them an e-mail saying my bank is not on the list, and after a couples of e-mails to and fro, I got an e-mail from a lady saying I must complete the form (which was attached in completed form to the original e-mail). Pointed out to her that she got it, and was then reassured that it will be sorted. Got another e-mail from DebiCheck (the same one as the first one), saying that I must complete the authorisation by clicking on my bank's link in the e-mail. My bank was, as per the first round, not on the list. I again forwarded this to the lady who said she will sort it out, to to be met by stony silence. A second prompt got a reply that it will be authorised from their side. Problem is, if we continue at this rate, I'll get the data in thime for Christmas.