I suspect you are using a Basic Bing Maps key which has these limitations: https://learn.microsoft.com/en-us/bingmaps/spatial-data-services/geocode-and-data-source-limits#account-limits-for-basic-keys
A single file upload for the data source API will be limited to 50 polygons, or 250 points. What you can do is make multiple uploads to this data source to append/grow the data source.
There is also a 50 item limit for the batch geocoding service. If you need more, you can either split your data and make multiple batch geocode requests, or you can geocode your data using the standard REST geocoding service: https://learn.microsoft.com/en-us/bingmaps/rest-services/locations/find-a-location-by-query
I suspect that your overall data size isn't massive, maybe a few thousand points at most and I suspect your data is fairly static (doesn't change that often). If that is the case, I wouldn't even use the data source API and would just store the data in a flat file, like CSV or GeoJSON to keep things really simple and fast. You can then either load all the data directly into the map, or write a bit of code to filter it within your app.
Here is an example that uses Azure Maps (newer Microsoft map platform) that creates a simple locator type app with a flat file data set as input (tab delimited file in this case): https://samples.azuremaps.com/?search=locator&sample=simple-store-locator