How can we get support from Quickbooks? Customers, Suppliers, and now bank payments appearing multiple times

One of my clients was using Quickbooks Desktop for many years, until they were persuaded to change to the Online version in 2020.  The data appeared to migrate across satisfactorily, and whilst there was some functionality missing from the Online version compared to the Desktop they changed their working practices to accommodate this and after a few teething troubles all seemed to be well.

In June 2021 customers and suppliers started appearing in duplicate, and sometimes in triplicate in the search box, and unless you clicked the "correct" one then you would get a message about the customer or supplier being inactive.  This obviously meant that it was taking up to three times longer to go into a customer record than it should do.

A lovely person called Danielle tried to help via the screen sharing thing on Quickbooks, and eventually decided the problem had to be escalated to Tier 2.  This resulted in us being advised to move office, buy a new computer and try again.

I dutifully did this, believing that it would make fudge-all difference, and was proved right.  I feel that there is a problem with our data files "in the cloud" as if it were a problem with the software or our devices or internet connections then more people would be having this problem.  From multiple conversations with QB support it seems that we're the only ones.

Anyway, I reported this back to Quickbooks the same day, and I don't know how I upset them, but to use modern terminology, Danielle ghosted me.

I emailed again for an update three months later, and she was still sulking.  Stoney silence.  

I waited until after Christmas, and emailed Danielle on the address she gave me ([email address removed]) and received an auto reply saying that Quickbooks had no recollection of the case.

Undeterred, I tried again.  This time, I spoke to the lovely Edelin and soon forgot about Danielle, just like she'd forgotten about my customer's Quickbooks problem and me.

Edelin sent an email asking if we had two-three customers in the customer list and told me to keep safe.  I replied in the affirmative and she soon went the same way as Danielle.

We carried on paying Intuit their £54 per month whilst grumbling about how tricky it was to use the search facility when everything appeared three times, but when bank payments started appearing in triplicate too, I emailed Edelin to let her know.  Much like Danielle, an email came back saying that they had no recollection of the case.

Yesterday I had a lovely chat with someone who had a name beginning with A I think.  We went through the motions with the searching, just like I did with Danielle and Edelin before.  I then showed A the bank problem and she helpfully suggested deleting the duplicate transactions, and sending feedback via the Quickbooks website.  She would feed back too.  Based on previous experiences I did not hold out hope.

Later yesterday I received an email from Quickbooks asking how they did.  I tried to respond as positively as possible - I felt bad about telling the truth, because the person I spoke to was lovely and tried hard, but I really didn't hold out much hope of the problem being resolved. 

The feedback survey had a new case number on it, so I emailed Quickbooks today asking for an update on the case.  Surprisingly they can't find this case number either. 

Apologies for the long-winded story.  I'll get to the point now.

1. Has anyone else had an issue with duplicate customers, suppliers and transactions?  

2. Does anyone know how we can fix this or should we look at another solution?

Thank you.