I also hope that you will find some work but I do think you are over-estimating the daily rate you can expect for house-sitting/pet-sitting, especially when a lot of forum members are pensioners and may not be able to afford €40/day. Sadly, your argument of saying you are not of retirement age will not persuade anyone to pay well over the going rate when there are plenty of people who will do this for €10/day.
Also, the fact that you state you were not adequately paid by your previous employer, I feel is not going to further your cause. Hopefully you would set a work schedule/daily rate/working hours ahead of accepting the post and you would have been within your rights to choose not to do any work over and above what you had agreed and quoted for, or renegotiate for extra requirements.
Maybe a better approach would be to advertise your house-sitting services with a contact number for people to call, explain exactly what they would require you to do, and then give them an appropriate daily rate.
I hope you will take this as constructive advice as I'm only trying to help you.