I totally agree and always put everything in writing. I've taken screen shots of the RM tracking result as shown above and kept all email correspondence with the buyer and will endeavour to communicate with the RM in print.
Finally managed to obtain a choice specimen F148 1897 high tide, after many years of one just eluding me. Private sale arranged with Cooper's Coins before it went on their website.
Special nod to Pete for the heads up.