payment arrangement

I have been unable to pay for my internet service do to be low income, I found out I qualified for lifeline after I had already started services with xfinity and was told that internet essentials was an option but Xfinity doesn't take lifeline, then I was told one requirement of internet essentials is that you must not have had service with Xfinity in the last 3 months, Xfinity is the only internet company in my area so i've been forced to keep on paying it , my balance is past due and the chat assistant offered me a installment on my past due balance , the deal was I pay a 50 deposit and they split up the remaining balance over 12 months, and by doing this my services would get restored , I said yes, i borrowed the 50 dollars and immediately signed up, that was 7 or 8 days ago and my services have not been restored. I called yesterday and was told by a rep and her supervisor that my services were not restored because I am not eligible for the installment plan. Why would you offer me a plan if im not eligible? why would you take the money and not honor it? 

why wouldn't I qualify for that plan? I'm low income as it gets. Can someone please help me. I have a child in school and its crucial to her education that we have internet access.

Thank you