Well, without seeing the configuration it is a bit hard, but I can suggest a few things:
– If you are using the index table engine, make sure the word length is set to 1 – because you want the numbers as well, and the lenght of 0-9 is 1.
After changing that, you will have to create a new index.
– Same with the keyword length on the search instance settings
– For the keyword logic, try the “AND width exact keyword matches” + “AND” as secondary if needed.