My N98+ phone can't make calls from fonebook

Hello,
My phone does not give me the access to make calls through the phonebook.when i go into the phonebook to retrive a name to make a call,it sends me to another window, where i find SIM1 IP DIAL,SIM2 IP DIAL,SEND SMS and the rest.But did not find CALL.I then went to CALL HISTORy,then to GENERAL CALL SETTING where i found IP DAIL.When i went into it,i saw some codes that i activated,thinking it could give me access to make calls through the phonebook.Ever since i did that, i have not been able to make calls at all through one of the SIM(SIM1),but can receive calls through it.SIM2 can both make calls and receive calls.The response that i get through SIM1 is "CHECK OPERATOR SERVICES" and the call is dropped.
Please how can i deactivate the IP DAIL or better still restore that part of the phone to enjoy my N98+ phone.Thank you.