DSL connection problem

[Psycho]

I have a crappy DSL provider already and just had Verizon activated on the same phone number. I attempted to hook up the Verizon modem but it can't connect. I assume the problem is that the old DSL service needs to be turned off first before verizon will work. Is my assumption correct?

 

[Xilikon]

Check with the crappy provider if the service is terminated correctly since i believe it's impossible to have 2 isp providing the same service on the same line.