I provide Internet services on a month-month or annual basis. Our T&C's provides contracts renew automatically unless cancelled with a signed 30 day written notice by account holder. No phone calls or emails are accepted. Late payment fee is $35. APR is 30% compounded daily. If someone fails to pay I have been charging the renewable service fee, associated late fee, and finance charges on the prior unpaid balance, but mostly late fees and finance charges. I'm assuming I can continue assessing fees until cancelled. I have tried repeatedly to contact the customer via mailings, email, telephone calls with no response or no resolution when I do get a response. I'm now threatening legal action. Am I able to continue to assessing these fees without it being considered unreasonable?The T&C's have always been available online and the customer were able to review and agree to these terms prior to starting service. Interests today on credit cards are as high as 29.99%. So it's not unheard of. What would make it not collectible? All these are business accounts, no consumer accounts.