Contacting sellers is not an requirement but it is desirable. Anyone, whether they are the Reviewer or not, can contact a seller and inquire about a listing. If you do not contact a seller, another Stamp Smarter member may be able to do it for you.

The general procedure is to contact the seller using the eBay messaging system. When contacting a seller we should always give them the benefit of the doubt and never assume a seller's intent. Everyone makes mistakes and without having the actual stamp in hand you should be careful about wording the contact message. Here is a typical contact message;

Good Day,
If you have the time could you take a closer look at the stamp in this listing? From the image provided this stamp appears to be a perf trimmed #35 and not a #15 as listed. Only the Type I #35 had incomplete side designs as shown in this image. If you examine the stamp please let me know your findings.
Regards,

Note the use of the phase ‘it appears to be’. Rather than drawing a hard line and challenging anyone’s expertise this approach is friendlier. At the end of the day we have to acknowledge that we are only offering a single personal opinion by simply looking at a listing. When we contact a seller the objective is to improve the listing for the benefit of all parties (buyers and sellers). This can only be done with the help of the seller. Even through this often means we are the messengers of ‘bad news’, most sellers are interested in doing the right thing. Be polite and professional, there is no value in arguing with a seller if their opinion differs from yours. Never become adversarial with a seller.

Generally speaking you should not mention Stamp Smarter; this is for two reasons. First, eBay has rules about linking/promoting websites with their messaging system. And secondly, you do not want the seller to think that it is being mentioned as a form of pressure or intimidation to get them to change.

When a seller responds we always note this in the Review although it is simply a summary of their response (never a copy and paste). It usually is something like ‘the seller responded promptly and professionally; but occasionally it might include something like, ‘the seller feels the stamp in question is not a forgery’.