Despite the fact, that this question is old and not that popular: a way of solution for everyone with the same problem:
It seems that the Billing/Invoice is indeed not allowed to be filtered AND it is limited to 50 items (.limit() does not work either). After trying this for serveral days I came up with a little workaround:
Create a "buffer" database, that is fed with the Billing/Invoice data regularly.. You can copy/paste the existing InnvoiceDatabase Items once into your new database and code a little snippet, that is hidden on a crowded site of your webpage. So every time a visitor enters this site, your bufferDatabase will get the new Invoices Data. Just make sure, that you update the data BEFORE 50 new Invoices-Items are sent to Billing/Invoices Database