You seem to list for only 5 days, so if constantly relisting unsold items 50 items listed 6 times during course of a month would use up you allowance.
Why not use 7 or 10 day listings, using 10 days you could list 100 items 3 times.
I am of course taking this in the simplest terms and taking all month 30 days, but it is a matter of taking full advantage of what you are allowed.
Selling on ebay at the moment is pretty dreadful, but over the years have tried other sites and they were awful even in good times on ebay.