But not delivered Saturday unless you pay £3.50 more!

I have bought something and asked to collect from Argos.It is sitting at the Royal Mail depot because today is Saturday and the seller did not look at the website where it is possible with skill to find Saturday is ££3.50 more.
Argos is !/2 mile from the Sorting Office.But nobody can collect the parcel till Monday

From Royal Mail website

Royal Mail Special Delivery [Nothing about SATURDAY HERE]
Guaranteed by 1pm®

100g£6.
45500g£7.25
1kg£8.552kg

£11.0010kg
£26.6020kg£41.20
Read more at http://www.postoffice.co.uk/mail/uk-guaranteed#v5q9RgWeWmlwU6F1.99

It is only if you read further down the page you see Saturday mentioned.

Quote:

Do you have a letter or parcel that is valuable or needs to be there the next day? Choose our Guaranteed services when you need:

• the item to arrive next day
• to track important items online and get proof of delivery, including a signature
• the assurance of compensation for valuable items
• seller protection if you are selling online

Royal Mail Special Delivery Guaranteed®

Get the peace of mind that comes with knowing that important post has arrived safely – use Royal Mail Special Delivery Guaranteed®.

Why use Special Delivery Guaranteed?

• Follow your letters and parcels from the moment it leaves your hands to the second it arrives with Track & Trace
• Choose to have your item delivered by 9am or by 1pm
• We’re so confident your item will arrive on time, you will receive a refund if it doesn’t*
• Your item won’t be delivered without a signature, which can be viewed online 10 minutes after delivery

What else is included?

• Up to £50 compensation cover for Royal Mail Special Delivery Guaranteed® by 9am
• Up to £500 compensation cover for Royal Mail Special Delivery Guaranteed® by 1pm
• Guaranteed Saturday delivery (additional costs will apply)
• Increased compensation available for up to £2,500
• Consequential loss (compensation for financial consequences of damage or loss) of up to £10,000 available for an additional fee

Read more at http://www.postoffice.co.uk/mail/uk-guaranteed#uSrxgmGeAfeev3tj.99

Read more at http://www.postoffice.co.uk/mail/uk-guaranteed#zO77y7z8udqS1RcL.99