Invalid Phone Number

I set up an account and then set up another using the same phone number. Then I switched to my first account and I discovered that my first account's is lo longer available. It asks me to use a different phone number. So I tried to logged in my second account to delete it so that I don't have to trouble with this. Then the system told me that my phone number had been recently used for a different account. So i tried to logged back to my first account and it also said that my phone number had been recently used for a different account. Now i can't logged in either my first or second account. Anyone know how to deal with this?