I'm trying to understand the restrictions on putting money into cash ISAs in the UK. Currently, the government homepage says "Every tax year you can put money into one of each kind of ISA. The tax year runs from 6 April to 5 April." (where cash is one of the 'kind's).
However, I've opened a cash ISA (in this, 2020/2021 tax year) with a building society (name withheld) and so far the customer service is dreadful; it's a long story, but essentially the account is still not fully open. As a result, I've put no money in and the balance is zero.
Can I tell them to close the account and open another with a different provider, in the same tax year, legally, since I haven't credited any money yet? The government advice seems kind of open-ended, but many other sources, such as Martin's Money tips, say "According to HM Revenue & Customs rules, you can only have one current year's cash ISA open at any time." (what does that even mean? what's a "current year ISA"?).
I looked at this question, but it deals with transfers, which is not my focus.