Reviewing a revision, after the original review did not reach the authors
I cannot say whether the situation is due to sloppiness or due to some technical issue but it seems odd and something that should not happen. I gather that you were in an electronic review system of some sort and then the review should automatically be forwarded. In a journal not working with an electronic system, something like this is more likely to occur but should be a one off mistake in any case. Problems like these, if they recur regularly, will likely sink the journal reputation in the end. you probably have some sense of the standings of the journal.

The lack of response may not mean much and I would not over-interpret it. It is of course not a positive reflection of the journal.

Anyway, I would recommend you to basically re-use your earlier review. Look through it after reading the paper and authors comments to see if anything can be removed. If you catch anything new that needs corrections, of course, add it. You have done the work once and unless the paper is completely rewritten with significant changes to discussion and conclusions, your comments still stand. You can only reiterate your verdict of Major Revisions, which should lead to a third round. I think, under the circumstances that would b fair, unless the authors fully comply with your suggestions, in which case the editors can use his/her discretion (depending on a second reviewers response of course).

So bottom line: your initial review needs to reach the authors but with corrections for whatever has been changed. Unless you receive some explanation for what has happened from the editor, you have to draw your own conclusions about the quality of the journal and particularly the editorship. Try to form a well-founded opinion, whether you think the journal is worth your attention in the future. One mistake is reason for caution, but not reason for judging.