Thanks for posting photos; they are important and helpful since they show the degree of asymmetry you noted yourself prior to surgery. You stated that your left breast was larger pre-operatively, and it appears as if your nipple areola complex was higher on the left as well. The second photograph was labeled "capsular contracture" but this simply appears to be an early post-op appearance ("high and tight" is normal at first). The right implant was indeed higher than the left in this early post-op view. The third photograph (6 months post-op) shows the breast mounds to be pretty close in size (volume) and reasonably symmetrical on the chest wall. However, the higher nipple on the left is still higher, and after the right implant dropped, the overall position symmetry on your chest wall is better, but the left is still a bit lower than the right..
If your breast volume (size) had been "perfect" prior to your surgery, you would have not required implants, and the only asymmetry would have been the (minimal) discrepancy between the two breasts in size, and the rather noticeably higher left nipple. If you had asked only for the nipple position to be corrected, your surgeon would have had to tell you that repositioning the nipple areola complex requires an incision around the areola (and of course, a permanent scar) on one and perhaps both sides.
Simply raising the left implant position will make that nipple look a bit lower and more symmetrical, but the breast mounds will be off (imagine the look in a tight sweater that does not show your nipples--the breast position needs to match, and that would take raising the left implant position only a tiny bit). Raising it too much to try to correct the nipple position entirely by suturing the bottom of the pocket internally will leave the left breast too high. And the left nipple will still be too high!
So, the best solution, based on your photographs (and a direct examination is better), would be a combination of tightening the lower pocket of the left breast (perhaps a tiny bit higher than the right since it will drop as it heals, and a bit of intentional over-correction will help to compensate for the naturally higher left nipple), plus consideration of a crescentic excision on the lower part of the areola to drop the nipple-areola position a bit on the left.
I have stated elsewhere on this site that I feel crescentic "lifts" hardly lift at all, and I still believe that after two decades of breast surgery and lots of "hardly-worth-it" crescent excisions in an effort to get a lift with a little scar. It just doesn't work very well.
However, a "little bit higher" on the left implant position, plus a "tiny bit lower" on the nipple position will help overall breast symmetry the most--though you will have a visible scar on your left nipple. Your augmentation must have been via axillary incisions (no periareolar or inframammary scars visible), so having to add one now on the left is a bummer, but would still have been needed if all you requested in the first place had been to lower the left (or raise the right) so they matched better compared to each other.
Your augmentation did not cause this; you had it in the beginning, and simply placing implants did nothing to correct the asymmetry. That, dear lady, will take a little more surgery! Talk with your surgeon; it is likely that he or she already sees this as well, and will be able to discuss the pros and cons of the approach I just outlined for you. Revision surgery costs should have been discussed prior to your first surgery; if not, discuss it now, so you know what to expect. Good luck and best wishes!