Unfair treatment

I received an sms noting I owe planet fitness for May and June, and that I am being handled over to the credit bureau.

I canceled my membership early April, as April was the last month of my contract. I don't understand how I owe planet fitness for the noted months. I sent emails regarding this and no response.

Can you please urgently fix this, as I don't owe you anything. THIS IS JUST UNFAIR, UNWARRANTED TREATMENT.