In my opinion, the phrases: 'the results' - refers to the specific results that will be refined; 'the categories', - refers to the specific (provided) categories; and, 'the left' - refers to the specific side (i.e., not the right side, not the top, etc.).
So, I don't think the word 'the' is overused.
ell.stackexchange.com/users/21978/shin
As others have said, your sentence is fine, as-is.
However, you might change it to "To refine your results, please use the categories on the left."
This would mitigate your concerns with the repeated "the".
ell.stackexchange.com/users/27099/Chris Goldman
As a native speaker, I can definitely say 'the' is not overused in this sentence.
The is one of the most common words in the English language, so often in fact you might use the word 'the' over 5,000 times in one day.
ell.stackexchange.com/users/27100/nkeck72
@shin is correct, the sentence is fine.
To refine results, please use categories on the left. is equivalent, but the difference is stylistic.
ell.stackexchange.com/users/26439/Peter
@shin is correct.
"The" is used three times in the sentence.
Each time "the" is used, the word that follows "the" gets qualified, becomes specific.
The sentence is ok.
There is no overuse of "the".
ell.stackexchange.com/users/26435/Dinesh Kumar Garg
For some reason I feel its overkilling on the use of article(the) here,    To refine the results, please use the categories on the left   Can someone help?
Am I overusing "the" in this sentence?
ell.stackexchange.com
<sentence-construction><articles><definite-article>
ell.stackexchange.com/questions/74502
ell.stackexchange.com/users/14217/uday
Your sentence is fine, as it is. There is no overuse of "the". The sentence is fine as it is. 'The' is not overused.
The sentence is fine as it is. 'The' is not overused.