Got myself into a silly pickle here in some ways. A long term client paid me for some services and I offered them a substantial discount. This was partly for their loyalty and they offered to pay upfront (but that's my norm anyway.) They used some of my services but then disappeared for a long time (over a year) but have now come back wanting to pick up from before. The thing is, my T&Cs have changed and my prices are much higher- more than double what they paid me. I suppose I ought to honour the agreement, but should they expect the same service for the cost it was a long time ago? I could refund them and say from now on it's on the new prices only, starting again, or reduce the amount of service I can provide based on what they paid. Any ideas?