The €70 is not an annual fee - you paid when you registered your property and this lasts for the duration of the tenancy, up to a maximum of 4 years after which time a new tenancy must be registered, even if you have the same tenants.
I would give them a call to make sure they received your registration. I registered two properties at different times and got receipts last year for both.
Alternatively, you can check if your propety is on their published register here. They're not strictly in alphabetical order so the best way to find your property is to use the 'Edit, Find' on the excel spreadsheet.