Welcome, Paula!
The withdraw limit is 50 credits, not $50. Each credit is worth 1 (Europe), or 75p (UK), or $1.20 (USA) if I remember well, meaning the limit is 50 or 37.50 or $60 depending on which Fotolia country you subscribed to.
The 365 days limit is for buyers. I don't think contributors' credits ever expire. Surely they don't before you reach the limit.
Yes, the submission procedure requires some effort but it's well worth in my opinion: Fotolia is among the first four sites in terms of earnings for most of us. It's no. 2 for me, actually. You can avoid choosing categories - which are optional on FT - to save time.
You must contribute to at least the big 4, and possibly a few more if you've got time.
While sales are almost immediate on Shutterstock, Fotolia requires some time but once you start uploading regularly and building a portfolio results will come. Don't give up!