CROSSED LINES CAUSING RELATIONSHIP TO END

this morning I phoned my fiance on his cell phone from my work landline number to let him know I was at work safe . it was a lady who answered on the other side so I asked what number or who was speaking, on my switchboard screen it showed that i had dialed the correct number yet it was a woman answering. when i put down my fiance was phoning and telling me that a man had phoned from my office landline number asking for a woman. he is now saying our relationship is over and that i got another man to call him and i am trying to make an idiot out of him. He says he phoned vodacom and telkom and they both say this is not possible - oh my dear Lord - can someone please help me - give me answers because it feels like my life is coming to an end and out of my control everything is against me