I have a friend that used InternetSecure for 4 months before cancelling with them (confusion regarding answers with presales questions, it was my friends fault more than InternetSecure) and he didnt have any of these problems.
Its kind of hard to believe these statements as they are recommended so highly on several sites like WebHostingTalk and no one else has posted anything like this. If it was a Authorize.net reseller like OnlineDataCorp, eDataOnline, whatever name they are using now, then I would believe it more (but thats another story).
As a side note, my friend and I both are using First Data now and have been very happy since we've been with them. If they are partnered with your bank, you can get some huge discounts with them.