NS&I ISA problem

Wishart

I have tried (correctly and legally) to invest in an NS&I ISA. I am registered with them on-line, but when I enter my NI number the message comes up that my NI number is already in use. Well, I'm sure my NI number is in use in many places, but maybe the problem is something to do with my holding NS&I Premium Bonds.
I phoned the NS&I 'award-winning' support team about this but got no resolution.
I emailed them and was told they could not deal with the matter by email. (Why not?)
I tried phoning again but still haven't had a resolution to the problem.
I emailed again and they replied asking if I wanted to lodge a formal complaint. No, I don't. I just want to invest in an NS&I ISA.
Can someone tell me what's going on?

ColdIron

You haven't given enough information to provide a meaningful answer. What were the reasons they gave you even though they provided no resolution

Wishart

That's the whole point. They haven't explained or given me a reason. I call them, they don't call back. I wondered if anyone else had similar problems with NS&I.

masonic

Could it be that some online account was created and associated with the premium bonds you hold, which is why it now won't let you create another? In which case, you could try going down the 'forgotten details' route instead of opening a new online account.