In August 2015 I started using Verizon Fios and I paid 100$ for security deposit. I terminated the service on July 2016. I paid all of my bills on time and had no debt. Although Verizon was supposed to pay me back the deposit after 30 days, it took almost two months and I called customer service several times to get my check. However, I got a new bill almost two months after I canceled my service in the same amount that Veriozn had to pay me the security deposit. Verizon reported my bill to a collection agency and although I called them and disputed the charge, but they put the charge on my credit report which dropped my score drastically.
I am sure that I have no debt to Verizon and the bill is due to the mistake of Verizon to send a check which has never been deposited to my previous address .
Please let me know how I can dispute the last bill that I got, and also how to get rid of the charge posted on my credit report.