level 7 very very bad service

I have been a cos toner for 3 years, I left the country with enough notice, 2 weeks earlier than expected, account was paid. equipment was returned 2 weeks later as I was not aware to return equipment, the account was handed over for 2 weeks late return of equipment. Then for 1 day correspondance with debt company, from 386.93 it went to 440, I refuse to pay that amount, as they handed me over without notice, they sent letter of demand for equipment which I returned n now want me to pay for the collection of it wen I returned it by paying someone else to go fetch n return, they are just out for money. debt collectors first time I dealt with them n they are just out to make money from innocent ppl, level 7 does not look after it's customers, wen I do come back to country, I will not use them n I will inform all ppl in our complex not to use them