I've neither misunderstood the situation nor being dense.
For the sake of clarity:
- OP has £750 in the bank for example, and has £160 worth of direct debits coming in
- OP buys phone for £600, leaving him £10 short to pay direct debit
- Result is - £600 phone should not have been bought
Whilst the numbers are examples, they must be representative of situation because the lack of £600 is causing him to be unable to pay his future debt.
What has happened:
- £750
- £150 -£600 for the phone
- £750 +£600 refund for phone
- £150 -£600 for the phone due to Amazon's mistake
- -£10 -£160 DDs
Same result, i.e. the phone purchase was not sensible in the first place.
Yes, it's Amazon's mistake. In fact, the argument isn't why someone would leave their bank account so close to the red - the argument is why would you be looking at £600 phones that would put your account so close to the red.
You might see it as mean, I see it as telling someone direct that they're better off reviewing their attitude towards money. Anything can happen in life, you only have to read the experiences of people that before March 2020 had comfortable jobs only to find themselves looking into financial ruin as their industry has been hit so hard.
This is why it makes sense to have easy access saving that cover you for multiple months of unemployment/other form of financial turmoil.