Internet/Customer Service

I called to customer service to inquire about the $50 internet plan for 5 years.  I got a rep Mark #9875 [Edited: removed private information].  he told me I had to purchase the modem for 125.00.  He said u already paying $25.00 a month for the modem.  So it made sense to purchase the modem.  I would have to pay my current bill plus the 125.00 so I agreed. Your bill will be 55.00 a month moving forward.  later I looked at the email information and none of it had my correct email and the account number for the payment was not my account number, During the call Mark asked for my banking information even the name of the bank.  I got worried and call back and the next rep stated that the previous rep had done something illegal to ask for all of my banking in formation and hold he would check with his supervisor.  he said everything had been done wrong and there is no such thing to pay $125.00 for the modem and he would have redo everything.  The new rep said he would have to charge me 85 dollars a month I had a credit of 125.00 on my account he would cancel the previous order.  I now feel like my banking information may be compromised.  I don't know what plan I have 55 dollar plan or 85 dollar plan.  Why did I need to pay an extra 125.00 for nothing.  This has not been a good customer experience.   Then on Christmas Eve I received 2 boxes from Xfinity 1 with a modem in it , and the other with a modem, extender and cables.  I called in the rep said I had 90 days to return it.  Why do I have all of this anyway.  I know a lot of customer service centers have been outsources but one doesn't know what the other is doing.  Please HELP.  Could I get some assistance with this matter?  I'm now in the process of canceling my banking information because of this.