The ongoing battle began in August, with Luna, known on the online platform as @lunahtic, made a number of posts documenting how an entire batch of the product had clearly gone off, despite the supermarket continuing to sell it.
Now Lidl has agreed at last to remove the oatmilk from its shelves, after Luna’s videos continued to draw further attention to the mouldy cartons.
Luna conducted a number of tests online and posted videos on TikTok showing the results, including comparing the oatmilk against other supermarket brands and following Lidl’s advice to simply shake the carton a bit more.
One experiment even saw her make one continuous video to prove she wasn't tampering with the milk, as she dashed into her local Lidl branch and bought a carton of oatmilk before rushing outside to empty the lumpy liquid behind the store.
However, the supermarket refused to stop selling the product.
In another experiment, Luna put the oatmilk through a blender in response to comments that she wasn't shaking it enough.
Lidl later offered Luna a £50 voucher, which she gave to her local foodbank.
In a post describing the problem, Luna said: “I only drink oatmilk, I can't drink milk, it doesn't really agree with me.
"The shop where I live is selling lumpy oatmilk. It's not just lumpy, it's like really sour.
“I first noticed it on August 10, and I've been buying this milk for years.
“So I've made about seven calls up and I was promised a refund because I bought 16 cartons, four each week. Then they said they're not giving me a refund despite me providing pictures and barcode numbers.”
She later added: “I bought a carton and opened it up in front of them - mouldy. They said you just have to shake it well.
I phoned up today, they are not prepared to take the cartons off the shelf. They're happy to sell their lumpy mouldy oatmilk.”
However, after the increasingly popular videos highlighted the problem, Lidl finally ordered all oatmilk made between certain dates to be recalled.
Environmental health are also understood to be looking into the situation.After a Lidl employee gave Luna a recall notice, she posted a video, saying: "This document shows that all Lidl oat milk in the UK up to the date stated on the letter has to be recalled.
"I spoke to my local Lidl store manager who did tell me the oatmilk had been recalled. I was told that new batches of the same oatmilk will be back on the shelves really soon and you can guarantee I'll be first in line."
In a statement to the BBC, Lidl said: "At Lidl, it is never our intention for a customer to be dissatisfied in any way and we work very closely with our suppliers to ensure that the products in our stores are of the highest possible quality.
"Following customer feedback we have recalled the affected batch and the product will be back in stores very soon."