It is surprisingly easy to contact your local MP or MSP these days, by email. You may be surprised by how quickly some of them get back to you and on the case.
If you are investigating an issue, or want an issue investigated, head over to any of these services so that you are armed with enough information.
The links at the foot of the page allow you to take a look at (selected) recent activity including public FOI requests (though you’ll also need to check each Public Authority’s own website to get more complete information of those sent directly by email or letter).