Subletting Agreement BLUNDER!!! Please help!

[Shantaviae Wynn]

I would like legal advice on a situation that my friend is currently dealing with. She moved out of her NYC apartment back in December 2016. Prior to moving out, she subletted the apt to a couple from Jan 2017 till the end of July 2017. She wrote a sublease agreement, they agreed to the terms and they all signed it. When the tenants paid their rent for June, they contacted her saying that they paid for the last month and are moving out at the end of June. She responded letting them know that the agreement states till July so they still have one month left. However, they are refusing to pay the last month and arguing that they thought the agreement was for a 6-month period (as it states in line item B). Even THOUGH she meant 6 month basis from January AND the dates are specified in parentheses. How do you recommend she move forward? I included an unsigned copy of the agreement for reference.