Since you want to correct people's post when they are clearly making a joke...
their
 
 /ðɛər; unstressed ðər/
Show Spelled[th
air; unstressed th
er]
Show IPA
–pronoun1.a form of the possessive case of
they used as an attributive adjective, before a noun: their home; their rights as citizens; their departure for Rome.
2.(used after an indefinite singular antecedent in place of the definite masculine form his or the definite feminine form her): Someone left their book on the table. Did everyone bring their lunch?
there
 
 /ðɛər; unstressed ðər/
Show Spelled[th
air; unstressed th
er]
Show IPA
–adverb1.in or at that place (opposed to
here): She is there now.
2.at that point in an action, speech, etc.: He stopped there for applause.
3.in that matter, particular, or respect: His anger was justified there.
4.into or to that place; thither: We went there last year.
5.(used by way of calling attention to something or someone): There they go.
6.in or at that place where you are: Well, hi there.
–pronoun7.(used to introduce a sentence or clause in which the verb comes before its subject or has no complement): There is no hope.
8.that place: He comes from there, too.
9.that point.
–noun10.that state or condition: I'll introduce you to her, but you're on your own from there on.
–adjective11.(used for emphasis, esp. after a noun modified by a demonstrative adjective): Ask that man there.
–interjection12.(used to express satisfaction, relief, encouragement, approval, consolation, etc.): There! It's done.