WWYD School dinners back payment

[Somermummy1]

I need a second opinion please

I pay for school meals for DS every week. Due to what has turned out to be an error on the caterers website payment portal thing, no payments were taken for vegetarian meals when he had them

I’ve been sent a bill for backpayments of £100 because it’s taken them so long to realise they had this problem with their system

I completely accept that I’ve had the benefit of the meals and I’m happy to make a payment but each week I’ve paid for the meals I’ve been asked to pay for

AIBU to think I should not now have to shell out £100 !!!???

Thanks!

Statute of limitations is six years, they are perfectly entitled to get you to pay for what you have received. Don’t be a CF