You should spend zero on your stock research company. If the management of the company actually had persistent skill in picking stocks, they would not be peddling their knowledge to the retail market for a few hundred dollars. They would rake in millions and billions by running a huge hedge fund and buy themselves a private island or something. Unfortunately for them, hedge fund investors are not as gullible as retail investors and are more likely to sue when they discover they have been lied to.
Many stock "research" companies are trying to manipulate you into paying too high a price for stocks. They buy a small stock, recommend it, and then sell it at the artificially (and temporarily) high price. Others are simply recommending stocks pretty much at random. You could do that just as well as they can, and for free.
Portfolio performance evaluation is a complex problem. The research company knows that its recommendations will "make good money" about half the time and that's enough to bring in a lot of uninformed people. To know whether your portfolio actually did well you need to know how much risk there was in the portfolio and how a competing "dumb" portfolio with similar characteristics fared over the same time period. And you need to repeat the experiment enough times (or long enough) to know the outcome wasn't luck. I can say confidently that your portfolio performance doesn't back up the claim that the research company has skill above and beyond luck. Much less $599 worth of skill.
I can also say very confidently that there are no investors with a total of 20 thousand dollars to invest for whom purchasing stock recommendations is worth the cost, even if those recommendations do have some value. Real stock information is valuable only to large investors because the per-dollar value is low.
Please do not give money to or otherwise support a semi-criminal "stock research" enterprise.