Strange things happening on our account

So here’s our story. Apologies in advance if I’m rambling

So maybe 3 weeks ago we had our account opened (took 2 months to get activated)
We started selling.
We were selling one particular product and it was selling well (MFN) not FBA
But then we noticed it kept saying
‘Inactive (Out Of Stock)’
So we topped it back up to 200 units
Then we noticed it kept going back to Inactive (Out Of Stock)
But if we added 200 units it would go to above 350
Then would go back down to 0. Then when I added 200 more units it would be over 1000
We didn’t make a sale since.
But then we noticed we were getting 800+ orders a week in our cancelled order section
That’s been going on constantly.
We are losing £2K-3k per day through the cancelled order section
We have had no reason why they keep getting cancelled
Only random listings do it. We have maybe 5/6 listings and 3 are definitely doing it
We have had big orders through FBA on the one listing, which would take us out of stock but it is still in ‘Pending’
We have sent items off through FBA and they have arrived, we have had confirmation that it is in our inventory. But it’s not showing up.
We have just sent out 2k worth of stock in one parcel and I’m afraid it’s gonna happen to that too

The listings keep changing description and pictures too so we have to pause our stock or raise our prices until the pictures go back. They tend to change when they lose the buy box.

We also have listings that we cannot get sales through. They all go to ‘cancelled’

All 3 listings now throw 90% of sales into the cancelled section and being honest, it’s winding me up.
Amazon claim that they are investigating at their highest priority. But nothing comes to light.

We are at a loss.
Just want to know if anyone else has a crazy account like us.

Almost forgot to add.
We also got an email from amazon saying our selling privileges have been removed. But they haven’t

Any help appreciated.
E&P