After unsubscribing, I will continue to receive ma...

After unsubscribing, I will continue to receive magazines. Email about this and the magazine keeps coming in the meantime. The employee points out to me that it is only a student subscription so that is why I have to pay it? And a day later I receive a letter that my subscription will be canceled from 2018. During our mail contact I also receive a registered letter with a demand to pay, because otherwise a collection agency will be involved .. A downright aggressive approach