Here's some for Christmas in my local London Camera Exchange:

SMC 50mm 1.7A £49.00
SMC 100mm M f4 Macro £129.00
SMC 100mm FA Macro £239.00
SMC 135mm M f3.5 x 2 £29.00 each

And I haven't bought these because I have just found:

SMC 50mm 1.7M £39.00
135mm Vivitar Close Focus f2.8 £95.00
28-90 Vivitar S1 £49.00
SMC 135M 3.5 £29.00

If you paid by Credit Card I would take it up with your Card Issuer. You should be protected by Section 75 of the Consumer Credit Act 1974. Trading Standards tend not to give much civil advice these days. It's been farmed out to Consumer Direct, operated by the Office of Fair Trading. Call them on 08454 040506

The Vivitar S1 70-210 (version 1,2 or 3) is a superb lens and I would pit it against Pentax any day. It is big (ish) an heavy because it is made of metal and glass. I originally purchased mine new in the mid eighties, first for a Pentax P30, then a Super A. Using it on a DL2 now - beautiful pictures.

Anyway. not the reason I am posting. As we all know the best thing about the Pentax cameras is that we can use our old lenses, and that the ones we could not afford new are now plentiful, but not for much longer, used. My original, and much loved kit, is a Vivitar S1 70-210, Vivitar S1 28-105, a Tamron SP 500 Mirror and a Vivitar 2X Macro converter.
The lenses go down to a 1:25 - 1:3 macro, the converter takes them to larger than 1:1.

After reading posts on Macro lenses ie Pentax 100m v Tamron 90 v Sigma 105 I have been scouring shops in London to see if anybody had anything in Pentax fit. I found two used Tamrons and a Sigma in LCE in the Strand but the prices they were asking were not much less than prices new. even though there aren't any new ones around at the moment. Then I went to Jessops in New Oxford Street asking if they had any Macro lenses in Pentax fit. Nothing on the computer, but the sales person disappeared into the vaults and returned with a Sigma 105 (not the DG), refurbished but otherwise brand new, for half the price of a new one. I grabbed it.

This is a lovely lens. The main reason that I needed a prime 1:1 macro is that I didn't want the hassle of putting a converter on the back of my other lenses. All the same I put the converter on the Sigma - I'm not sure what magnifications I am getting now but you could say this was the Bee's Knees.

Also recently purchased an old Vivitar 28mm f2 on the cheap. Another cracker, which on a digital is equivalent to 42mm. And with the Converter on the back a stunning 84mm Macro lens.

If you want a good 2X macro converter try to find the Vivitar (7 element, not the cheapo one). Many posts on the web say it is the best ever made. It turns any 50mm lens into a 1:1 macro, or into a 100mm telephoto. It also doubles the length of any other lens, and turns them into macro as well. And after years of use I can also say that it improves the quality of any lens, at the loss of two stops. You should see what it does to the Vivitar zooms.

Back in the eighties bought a Pentax P30, then upgraded to Super A, with Vivitar S1 manual focus lenses that had the 'A' aperture setting. Also had the FD550 flash. Fantastic quality. Became redundant after I purchased a Sony Digital compact three years ago until Pentax produced an affordable Digital SLR. Compacts aren't the same are they? A few weeks ago purchased a DSL2 from Jessops, mothballed the 18-55 lens that came with it and attatched the Vivitars. Stunning. Put the Camera on Manual Focus Aperture Priority f8 and fire away. I am so pleased.

The Flash works as if it was on the old Super A - just set it to TTL.

I have the Vivitar S1 70-210mm mk 3 and the S1 28-105mm. Also a Tamron SP 500mm Mirror from the same era. They all work beautifully.