Incompetent technical-IT team

I haven't had any issues until recently, and actually the platform works OK. On May 4th, all of a sudden , the card that I always used to deposit funds with returned a 'billing address doesn't match please change your address in settings' error, although I had never changed my address or any of my personal details.
When I called them, they first asked me to send bank statements as a security check -which I did immediately.
It has been almost 20 days now, and I still cannot deposit funds and despite numerous calls and email exchanges, IG still can't fix such a small technical issue.
You actually speak to some nice and polite customer service people, and some of them are genuinely trying to be helpful, but clearly their IT team is not competent enough to handle what should be a simple technical bug.
Over the last 3 weeks or so, I interacted with close to 10 different CS rep at IG and we tried things like :
-deleting the card and re-adding it
-adding a space to the postcode
-changing the address so everything is in on line
-CS rep NC asked me again to send bank statements, for no reason, when I told him that I already did, he didn't even get back to me and disappeared
-then they asked me to contact the bank and change the address from their end ...which we did ...and the bank confirmed that all 24 attempts were all declined by IG systems.
-at some point, CS rep D told me over the phone that other customers were also having the same problem, after the phone call sent me an email telling me again to change the address in settings and contact the bank in a weird series of emails and contradicting statements.
-then we tried with CS rep S .. a few calls and emails with her, then she gave up and stopped responding to my emails

Each time I ask for an update , they simply say that 'it is being investigated by IT' and they suggest making another change in the address line..
The way they handle this is issue is simply ridiculous.. this elusive 'IT team' cannot be reached, no one can speak to them over the phone and all they can say is : 'it is being investigated and we will inform you as soon as we get an update'

This is absolute nonsense IG..if you are dealing with millions of pounds of investments, your systems and IT support should be robust enough to fix these bugs immediately. 3 weeks to investigate a simple address mismatch..this can't be attributed to Covid-19 disruptions... Your IT team's incompetence is beyond human understanding and because of a stupid technical bug I am now forced to move to a another platform.