Underpaid by SFE due to their error

Hi, I'm not sure if this is an issue any of you are aware of or have come across yourself. A friend of mine ran into a particular issue with SFE, which apparently according to SFE themselves, is really rare and only occurs once or twice.
She's going into 3rd year right now after having a nightmare with SFE in her 2nd year. In January SFE were supposed to give her £1.5k but it eventually became revealed that this was paid into another account, not hers. After contacting SFE they said they can't really do anything because on their system it says she received the 1.5k. She tried chasing it up but to no success, and had to essentially scrape through with her own savings to get by. Every time she contacted SFE it's as if they say something different each time, and the last woman she contacted reassured her this wouldn't occur in 3rd year.
Turns out it did affect her this year, because now SFE have considered this £1.5k as her being "overpaid", which is confusing. But that means she's getting less off her usual amount for this year, which is already the bare minimum of approx £4k.
She's tried complaining via email once but no reply. Does anyone know what she can do to fix this issue, as this seems entirely unfair?

Hi there, if she calls us on 0300 100 0607 we can look into this for her and help her further. Thanks, Jason

That’s the number she has been contacting ever since January, the same number where each person she calls they say something different. Is there another way she can reach out, or another number?

Hi there,

That is the only number we have. If she hasn't receive the payment into her account she would need to send her bank statements to us and covering letter explaining the situation and we can investigate this.

Thanks,
Claire

Hi, that could work, to which email address should she send all of this?