I'm not sure this is actionable. For nuisance/right to quiet enjoyment (which does not mean "quiet" as in "silent"--it is a legal term of art) a reasonable person standard is used. Would a reasonable person be so bothered by this that it would in fact deprive them of the enjoyment of their living space? People's sensitivties are not taken into account, and the judge determines if its reasonable (or jury, but with things like this, people usually go to small claims court). If you are the only one complaining, it may look like you're just sensitive. See if anyone else would join you in complaining again. Your best bet is the internal procedures. Otherwise, you'd have to sue to get a court order changing the lock, and based on what you present here, I doubt it will be successful.
This is a complicated issue because it may or may not be subject to arbitration before the Department of Business & Professional Regulation (DBPR), which is less expensive then litigation, but still costly if you lose the case because the Condominium Act provides for the prevailing party (winner) to recover attorneys' fees.
An arbitration case can cost $2,000 to $20,000 depending on how hard the association defends itself and a civil case in court can cost five times that amount. These cases are not done on a contingency because there are no big damages to be awarded.
If you are seeking to have the association change the lock again and are not seeking compensation for personal damages, DBPR may hear the case, but first you have to send the association a certified letter outlining your dispute and your intention to seek arbitration pursuant to FS 718.1255 if the issue is not resolved. You would then need to file the petition (not a complaint form, but an actual petition for arbitration) and pay the filing fee. If DBPR claims they do not have jurisdiction, then you would need to seek an injunction in county court.
It sounds like your association is trying to be reasonable, so try approaching them again and see if you can offer some suggestions for the type of lock needed. Problems are more often solved amicably when you bring a solution with the problem.
This communication is not intended to create an attorney/client relationship. It is always recommended you consult an attorney in person to discuss your case. The Law Offices of Stage & Associates practices state-wide and represents homeowners and community associations. Please visit our website at www.stagelaw.com.