You should have recieved them by now so they may have got lost in the post.
Did you get a message from giffgaff saying your sims has left the building please check
Click on the link below and scroll down to from giffgaff.
Bu you can always order two more sims as it doesnt matter if the others do turn up.
Or you can click on any gaffers sim banner.
All the best Bob
Giffgaff sims are packaged to look like junk mail, which means there's a high probability of them being thrown away with the daily pizza adverts if you're not the first person that sees the mail.
So, order again and make sure that anybody else at your address knows you're expecting something with a prominent giffgaff logo.
Alternatively, if you're in a hurry, you can probably get giffgaff sims for about a pound in some local shops, but then you will not get the £5 bonus credit that you might have got if your sim came from an existing member or a member banner.
Are you sending to a private residential address in the UK ?
There have been unconfirmed claims that giffgaff has some blacklisted addresses or address types, but nobody has been able to establish a pattern.
Is there perhaps a different address you could have the sim sent to? Preferably, a residential address with just one family occupying it.