Terrible service

I received a summons for an account that should be settled. I tried calling the number provided however it constantly rings, no answer. I also tried sending an email but the address is not valid. This is terrible service as I am trying to contact the company regarding their alleged arrears but to no avail. I am unable to appear in court due to Covid. Hence I was making contact. How can a company just send out a summons without contacting me.