Some thoughts:

First off, 14.Nxf7 is a beauty of a combination, but you should have been checking out thematic sacs like that in a correspondence game rather thoroughly.

Next, the Colle system is a good positional opening which I suppose a lot of correspondence players employ, since books of theory and memorized variations aren't much use in this arena. Often it's considered sort of a wimpy opening, perhaps because that QB is locked away, but the Colle player has a plan to liberate it by working on playing e4 at the right moment. He can't do it immediately because he ends up with an IQP position that looks inferior to other popular IQP systems, but he can play dxc5 followed by e4 to liberate his QB. (This reminds me of the semislav strategy, where Black's QB stands in the corner pitiful and useless, but he has a very sound plan to eventually let the lion out of its cage.)

With that in mind, it seems to me that 7...cxd4 is very anti-positional. I'd go so far as to say it's the losing move. If the Colle is considered wimpy because the bishop is locked away, and if White is expected to do all that work to solve his problems, then make him do that work! Your move ...cxd4 solves all of his problems in one stroke. All of a sudden he has everything pointed at your kingside!

Also noteworthy is that this is a classic case where White wants to take the old adage "pawns capture toward the center" and toss it in the rubbish. Only a patzer would play 8.cxd4?, a good player would recognize that the scope of his bishop is paramount in this position. This should be obvious, but it's interesting to point out situations where these 'positional rules of thumb' we all have memorized have to be weighed against the realities of the position.

Finally I leave you with this game to look at: Colle vs Rubinstein, 1926, Akiba takes Colle's own opening, swaps queens, and quickly turns it into an ending where he's a wee bit better.

The Colle is one of those openings that everybody has to cope with. When you have the Black pieces you never know if your opponent is one of these system woodpushers. I've heard of 12 year old kids learning it from their chess coaches, and I've heard of people who got good enough at the opening to push themselves into the master level without any other weapon in their arsenal.

I am not in your league, but since you were kind enough to offer me some feedback in the Cafe on one of my games, I will attempt to return the favor (if a patzer's advice can be regarded as a favor rather than a hindrance) by offering a suggestion or two here.

It seems to me that after 10.Ne5, 10...Ne7 ignores the problem you are facing from White's strong, centralized knight. While the e5 square is not technically a hole, since the advance of the f-pawn to f6 can drive it away, that would require the removal of your knight from its defensive position on f6, and in this position that would likely be a mistake. Not only does White's knight on e5 prevent your e-pawn from advancing (thus giving your queen's bishop a much needed egress), it covers the d7 and f7 squares, has a great deal of influence and mobility, and sets White up (possibly) for various combinations, since in addition to the knight at e5, White has a bishop pointing at h7, another knight which can move to f6 and thence to g5, and so forth. In fact, that knight on e5 is suffocating you, and something ought to be done about it right away, while it is still possible to reduce White's positional advantage.

I suggest 10...Bxe5; then 11.dxe5 Nd7. Now you might face something like: (a) 12.Nf3 f5 13.Bg5 Qc7 14.Qe2 Nc5 15.Bc2 Ne4, at which time your position seems to me to be improved. Or, you might face a reply like: (b) 12.Qh5 f5, which also strikes me as an improvement. In both cases, White's strong knight has been removed and he cannot place a piece in the hole on e5 since his own (now attacked) pawn is there.

This can be done if you expect your opponent to use a dutch stonewall formation e.g. 1. d4 d5 2. e3 then 2. ... Bf5 follows. Or in this case against the Colle it would be: 1. d4 d5 2. Nf3 Nf6 3. e3 Bf5. To me it appears that with these two systems white is aiming at controlling e5 in both situations although the openings are obviously quite different.