I’ve renewed my premium subscription this week just to discover that some of the premium features got removed. Mainly Chat/Grammarbots (removed from the app, disabled on the website).
Grammar got added in simplified version as free beta feature.
And there’s no announcement that I can find about these changes or what we can expect as subscribers.
If you care about your paying members maybe you should show even tiniest bit of respect instead of leaving them clueless of what to expect.
Hello kwarkje 
I am just a user, but I would like to comment on some issues that maybe help you (while you expect an official response from Memrise Support).
For the past 60 days, I have not read any official topic stating that chatbots or grammarbots would be modified. But MemriseMatty reported that in the app was created a Grammar Sessions on Android (click here), as you already noticed.
I noticed that the initial modules of the official courses of most languages were changed about a month ago (for British English speakers). French, German, Japanese and Italian are some of them.
The official courses usually have 7 modules, and modules 1-2 have been changed (in the case of Japanese, module 0 added as well). But the web version of the new courses had some problems. I reported some of the problems here.
I do not have PRO so I can not test, but maybe the problems with chatbots and grammabots are related to the new courses. Or maybe Memrise is thinking of modifying the system of the new courses?
You could test with modules that have not been exchanged and have (or had?) chatbots / grammabots, such as module 3 of those courses. Or the old version of these courses. Old versions can no longer be seen on the course page, only new versions. If you do not have them, you need to ask people who added the old versions before the update. Or get an old link in the forum.
The chatbots/grammarbots have been removed globally as far as I can tell and replaced with the new grammar tasks (which are not available on the website making it even worse there) I have German, Italian, Spanish, French and EU Portuguese from British English in my deck
Yes, I can see that you have these courses 1-2 in these languages, but if I can see it on your learning list, that means they are new courses. If you have the old courses 1-2, I can not see it unless I have them added to my list as well. And the only old courses I have are Japanese.
Or maybe you have the new and old too (both versions)? If you have both versions, I will only see one of them (the new one).
Try to only add course 3 of French or Spain, to check if chatbots / grammabots is still not available (Portuguese or German for UK English speakers does not have chatbots). But remember that: this feature will become available after you’ve learnt at least 4 words in the course.
EDIT: But as you said in the first post you made a renewal, you have already used chatbots/grammabots in some course. And if in those courses, these modalities do not appear anymore, you’re right, and we need to wait for a response from Memrise.
Yeah, as you’ve mentioned I had them all finished in my courses. I had some just for chats/grammar and videos. And now they’re gone.
The new grammar tasks seem to have wider reach but they’re borish, unengaging and haphazard. As long as they will keep expanding them often (I doubt) I’m fine with that.
Levels above 2 seem to have old chats, but they’re just the ones from old level 1 repeated.
And they’re broken, completion through website doesn’t register.