To submit a request, either start at the login page and click Support (that's faster) or send an email to
support@fastmail.fm, wait for the autoresponse, click the link, and complete the form.
The problem over this past weekend has been fixed, as discussed in other threads. FM turned off greylisting (it's unclear whether this was accidental or the result of some load balancing required) but re-enabled it yesterday.
If you are seeing spam increases over the course of a month, even very large increases, it's unlikely that FM has anything to do with it (other than blocking more than you are even aware of). Though most surveys show total spam levels either stable or growing only linearly (as opposed the expoential growth seen for several years), the spammers operating seem to be getting ever more aggressive, and the movement is away from simple sleaze and toward outright fraud. So you may just be seeing this increased aggression.
Or your email address may have slipped out and is now starting to circulate among the spammers.
When you say "greatly increased", it helps to give absolute numbers. For example, last weekend, mine increased from 30-40/day to around 150/day. If you are looking at an increase from 1/day to 5/day, then although that's indeed a great increase, most of us would say count your blessings ... and prepare yourself for worse.
Edward