Is it considered slander if I was terminated when an employee with an affiliated company began complaining about any petty thing?

I discovered that a former colleague with another company was sending my boss’s complaint emails regarding me. Any issue that arose out of basic communication was taken was out of proportion and made me look like I wasn't being a considerate and cooperative employee. During my dismissal, I was told that they got too many complaints. I believe that there was only one source for these complaints and it was not filtered through her boss. The complaints were directed at my boss too and I was let go. Does this sound like defamation of character and slander with intent to cause harm?