Shocking Service From Iron Mountain Accounts Department

We have received nothing but problems from Iron Mountain, previously Shred It. For about 5 years I have been trying to resolve invoicing issues with our account. The finance division is a shambles and certainly could use some qualified people working on the corporate accounts. We have 11 branches and I have had issues with all the invoices. We pay invoices and then receive duplicate invoices billed on a different account number for the invoices that were paid. It has taken 5 years to have some of these invoices credited whilst other invoices have been billed using the incorrect amounts and we are still waiting for credits. To top this all off, I needed to send Iron Mountain copies of our contracts to confirm our billing costs. I requested all proof of payments from our bank dating back to 2018 and have reconciled their account for them several times. We were also fortunate enough to received invoices for April 2020, our offices were closed, and no services could take place for which I have received no proof of service from them and no credit notes either. Then, lo and behold, our services are suspended due to non-payment, yet 2 months ago I offered to settle certain invoices I felt may be due to them on condition I received the required documentation. Recently we have received invoices for services with no details of where the service took place. Iron Mountain cannot give me completed work orders for these invoices either but expect payment. Iron Mountain should be shut down in South Africa. If they can't get their accounts straight, how can a business trust them with anything else?