Say there's a clause (art. 14) that creates an obligation for party A, from which an obligation for party B follows. Say it looks like this:
art.14. Every year, no later than six months after the end of that calendar year, Party A will provide Party B with a section-by-section overview of the costs for service A.
art.15. What appears from the overview, taking into account advance payments made by Party B to Party A, whether Party A has been paid in advance too little by Party B or Party B paid in advance too much to Party A, must be paid or repaid within one month after the overview has been provided to Party B.
These articles happen to be in a
General terms and conditions document that is part of the contract, through an article in the contract that says that the general terms and conditions are part of the contract.
Party B happens to have been negligent and considered the advance payments as flat rate for the service. This understanding came to Party B partly because, according to Party B, that is how the agreement was presented by Party A, contrary to the letter of the agreement. This understanding comes also partly from previous clients of Party A, who also considered the fixed monthly payments as flat rates that do not need settlement. These clients used the service for years, stopped using it, and never received an overview for settlement according to art.14.
For more than 5 years, party A ignores their obligation regarding art.14. and never mentions it. Party B does not try to enforce art.14, because, in their mind, such an article was never part of the agreement.
In the second half of the 6th year, Party A tries to enforce art.14, by providing an overview for settlements over the previous 2 years going backwards from the moment of submitting the overview.
- Party A demonstrated a history of not fulfilling their obligations according to art. 14 in relation with Party B, but also in relation with other Parties with whom it had similar agreements.
- Party A never mentioned article 14 from the general terms and conditions at signing.
- Party B never objected to Party A not fulfilling their obligations.
I would argue that there was an implied in fact agreement that the advance payments are fixed flat rates for service A, because both parties met in mind and abided by this agreement through their actions, i.e. Party A never submitted an overview, and Party B always paid the advance payments in time.
This implied in fact agreement of parties goes in conflict with art.14. Provided that the implied in fact agreement stands legal scrutiny, and considering that meeting of minds must have happened after the signing of the written agreement, the implied in fact agreement is newer, thus supersedes art.14 of the written agreement.
For what is worth, the situation stems from a rental agreement in the Netherlands, so EU/Dutch law applies to the original case. Nevertheless for the purpose of this question, I am interested in what principles of law apply, especially from civil law, but I am also curious of an interpretation according to common law.
I am not a legal expert, but I am familiar with some principles of laws. The above is a working example, but my general question is whether a clause in a written contract is valid and enforceable, if all parties took regular actions contrary to the clause for a very long time without any dispute. An analogy to the above situation would be a written agreement of parties that monthly, 10$ would be exchanged for a selfie, for a period of 20 years. Then 19 years pass and nobody ever sent a selfie, or 10$ in exchange, or took any action with respect to that agreement, but one party starts sending selfies (many years later) and asks for their rightful 10$. In my mind, that's just crazy, but then again, I'm not a lawyer. What do the experts think?