" Very difficult to access phlebotomy service"

I registered an online request for a phlebotomy appointment and received a callback within the 48 hours specified. However, the caller rang off after a very short time: I think the only way I would have been able to answer was if the phone was on my person. A voicemail message asked me to phone back, but the number was NoCallerID so the only way to call back was to phone the central number - number 60 in queue and strong suggestion I book online. So back to square one with another online request for a callback. I wonder what % of callbacks are registered as ‘unable to contact’ because insufficient time is given for the patient to respond? This wastes everybody’s time. I appreciate the heavy demand but surely a service like this should have an online booking system and not have to rely on harassed call staff.