Has anyone else had accounting inconsistencies with their customer ledger?

I had a customer reach out and tell me they had received a past due notice and they had already paid for the month.  I accessed the ledger and verified there was a balance on the account and relayed that to the customer.  The customer insisted they had a receipt showing 0 owed.  After further investigation, and a multi hour conversation with Sitelink levels one and two, I finally got Sitelink to understand (thank God I come from a collections background) that the ledger cannot show one amount, and a receipt a totally different amount.  The answer from Sitelink?  Well, we must have a bug.  We will remit it to the next level and it will be resolved but we cannot tell you when because it gets prioritized by issue.  Wait, what?  Why does Sitelink not have the same priorities that we do as business owners?  Just curious if they expect you guys to continue paying your best money to them while they "prioritize" their software issues or in plain English - do not provide us their best work?  I mean, they are cashing my checks, so I think that means they agreed to do the work they've been hired for?  Like, now?  My customers would not care if I had things to do that I felt were more important than them, nor do they care what my staffing issues are - they would go elsewhere?  Am I crazy here? Has anyone else experienced the same ridiculousness?  NO ETA?  Really?  What do we tell our tenants?  Our system is not reliable?