It's great saving time by doing your supermarket shop online - until you realise you're going to have to go to a store anyway because your delivery doesn't contain what you ordered.
When supermarkets haven't got the particular item you've ordered, they'll often send something else instead. According to Which?, Asda is the worst offender for this, with nearly half of customers saying they've had a substitution in their online shopping in the last six months.
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Amazon Fresh, was next worst, with 37% of customers receiving substitutions, with a third of Waitrose Deliver customers and 30% of Tesco Online saying the same thing.
Generally, these substitutions aren't too much of a problem: most people don't really mind if their chocolate digestives aren't the usual brand.
It's much more annoying, though, when vegetarians are sent meat products, as they frequently are; or when nappies arrive completely the wrong size. And, as a recent thread on Mumsnet demonstrates, it can be a nightmare when the wrong Christmas order arrives.
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But these substitutions can leave customers scratching their heads all year round, as Which? has discovered. Here are its top ten bizarre substitutions.
1. 'I received a sack of onions when I had ordered a bottle of white wine.'
2. 'I got extra strong mints in place of beef mince.'
3. 'I once ordered a pack of condoms for my husband and we received a pregnancy-testing kit – presumably for myself!'
4. 'Dog food was put in instead of clothes hangers.'
5. 'I got sent a bar of Dairy Milk instead of a premium salad.'
6. 'I ordered mayo and had it subbed for window cleaner.'
7. 'I received nappies instead of toilet paper.'
8. 'Baby food was replaced with tampons.'
9. 'I was given a bottle of Chardonnay when I wanted some apple juice.'
10. 'I ordered gluten-free bread and got dog food.'
11. 'Tissues substituted for sausages.'
12. 'They sent tinfoil instead of bin liners.'
13. 'I asked for a punnet of peaches and they substituted it for peach shampoo.'