Installation not done from last one month

Hi, <br> <br> I have app**** for installation of Land line Order NO : ***A in mid of September. I received a SMS for installation on 22-09-2015 but no one turned up . After multiple call to call center and help chat i got another istallation date as 30-09-2015 but still no one turned up. Then i called multiple times to Telkon call center , every time i got response that we will talk to the engineer and get back to you / But till now no one called me back. <br> Finally in a call on 09th Oct , i got a installation date as 15th Oct . Today i got a SMS about installtion on 15th OCt but still not sure if the engineer will turn up. Is there any way we can make sure that engineer definitely turns up on 15th OCt 2015.