Multiple critical errors & no reponse to support cases

We are having critical errors with MYOB account right where it is posting unbalance values in journals, inventory, bank reconcilliations and so on. 

Such as an payment to an creditor for 3 invoices for an total of $2211.83 but the bank reconcilliation shows the amount paid of $1684.93 to be reconcilled. I am unable to delete the payment as MYOB says that it can't delete a deposit transaction for a recorded purchase. Huh? What does an creditor payment have to do with an deposit transaction???

Another recent critical error was with an common item that we sell where every sell was adding to the inventory on hand and value instead of deducting and I had to solve this with a series of deleting sales and re entering them and manually calculating inventory adjustments. (case #01995145)

These are critical errors that should not be able to occur and have occurred in the last 2-3 weeks which indicate there is an critical error somewhere that is causing these entries that should be immpossible. 

I have submitted an number of support cases that are so far being ignored. Cases #02020790 & 02026546

We have been told that support will be getting back to us on the cause and solutions but we are still waiting. 

Is there support for MYOB account right? Is MYOB fit for purpose?