Not Releasing Our Line To Move to New Isp

We need them to release our fibre line as moving to Mweb. Been on hold for 40 minutes twice today waiting to speak to a human in the sales department, and have yet to do so both times. First time was cut off because my airtime had been depleted and so had to recharge and get back into the queue. How can a sales department on the 30th of December be so busy that one can be on hold for 40 minutes with no answer, but billings and tech support answer within 5 minutes????